
rte TJiyy 

Book 

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COPYRIGHT DEPOSIT. 




W I 



Practical 
Stationary Engineering 



IN FORM OF 



Questions and Answers 

BY 

A. C. WEST 

FORMERLY 

Chief Engineer Charles H. North & Co., Packers 

Chief Engineer Walworth Mfg. Co. 

Chief Engineer Copley Square Hotel 

Chief Engineer Mass. General Hospital 

Chief Engineer Woodland Park Hotel 

Inspector of Steam Boilers 

Manager Franklin School of Engineering 

CONTAINING 

Information relative to 
Steam Boiler, Steam Boiler Accessories, Riveting, Bracing, 
Steam Engine Indicators, Indicator Cards, Valve Setting, 
Pumps, Condensers, Etc., with simple Arithmetical Rules 
for computations and one hundred illustrations. 



Copyright, 1909 

BY 

Andrew C. West 
Boston, Mass. 



248849 



PREFACE. 



The author, a practical first-class licensed engineer of long and 
varied experience, has for some time felt the need of a clear and con- 
cise work by which the average fireman or engineer may perfect him- 
self in his chosen profession, as well as prepare for the necessary ex- 
aminations essential to his advancement to higher grades. In per- 
fecting his book, he has endeavored to make it as simple as possible, 
and, wherever practical, has eliminated all traces of technicality and 
formula. In place of the former he has given the common names and 
phrases, while the latter is substituted for simple arithmetical rules 
that can be easily worked out by any one understanding addition, 
subtraction, multiplication, and division. During his thirty years' 
experience as fireman, engineer, and mechanical superintendent, to- 
gether with the experience obtained as instructor and manager of 
engineering schools, he has had the opportunity to become acquainted 
with the requirements of the fireman and engineer. He has carefully 
observed and noted the various stumbling-blocks so likely to confuse 
not only the beginner, but also the man who in every-day practice 
finds some point upon which he desires to be enlightened. 

The author wishes to state that this work cannot be read as a story, 
but requires careful study and its answers committed to memory, to 
be expressed in the student's own language after he has clearly under- 
stood the points desired to be brought out by the writer. 

To the man striving for a fireman's license he would advise thor- 
oughly mastering the questions and answers pertaining to boilers and 
boiler accessories. 

For the third-class engineer he advises study on subjects previously 
mentioned, together with the text on engines and valve setting for 
the simple slide valve and riding cut-off valve. 

For a second-class engineer he advises study on all the subjects 
treated in the works, with particular attention to the text on indicator 
diagrams. 



IV PREFACE 

For the first-class engineer, he must be thoroughly acquainted and 
able to answer all questions contained in this book. While he may 
never be called upon to answer more than one-half, it is safe to know 
them all, as no hard-and-fast rules are followed by the inspectors at 
examination. 

The difference between the first-class grade and the second-class 
grade is a more thorough and stringent examination of the first- 
class. 

The work fully covers all examination questions liable to be asked 
the applicants by the State Examining Board. 

The writer will be well repaid if through this volume the student 
finds means of improving his condition or of advancement to a higher 
grade. 

To the following-mentioned manufacturing companies he desires 
that credit be given for supplying information and electrotypes 
relative to their product: American Steam Gage Company, Boston, 
Mass.; The Locomotive: Hartford Steam Boiler Inspection Company; 
Mason Regulator Company, Boston, Mass; Putnam Machine Com- 
pany, Fitchburg, Mass.; C. H. Brown & Co., Fitchburg, Mass. » 



CONTENTS. 



PREFACE iii 

Chapter I. 

BOILERS 1 

Upright Boilers 17 

Water Column 21 

Babcock & Wilcox Boiler . 23 

Heine Boiler . '. 26 

Steam Gauge 27 

Fires 30 

Corrosion 32 

Oil or Grease 33 

Blisters 35 

Foaming 36 

Staying 37 

Boiler Explosions 38 

Inspection and Testing 40 

Inspirators 41 

Water per Horse Power 43 

Heat 44 

Chapter II. 

SAFETY-VALVE 47 

Tubes * 54 

Boiler Plates . 60 

Bursting Pressure 60 

Area of Boiler Head to be Braced 66 

Chapter III. 

RIVETED JOINTS . 72 

Single-riveted Lap Joint 82 

Double-riveted Lap Joint 83 

Double-riveted Butt Joint 87 

Triple-riveted Butt Joint . 90 



CONTENTS 



Chapter IV. 

HEATERS 96 

Damper Regulator . 99 

Heating System 99 

Traps . . 102 

Ventilation 105 

Reducing Valves 106 



Chapter V. 

ENGINES 108 

Absolute Back Pressure 109 

Clearance . . Ill 

Cut-off . 112 

Piston 114 

Connecting Rod 115 

Solid-end Rod 117 

Key, Gib, and Strap 118- 
Key Room 119 

Eccentric 119 

Compound Engine 122 

Valves 126 

D Valve . : 135 

To set Common Slide Valve 136 

Valve Setting for the Putnam Engine ....... 140 

Riding Cut-off Engine 141 

Corliss Engine 145 

Valve Setting for Corliss Engines 146 

Dash-pots : 149 

Brown Engine 150 

Piston 150 

Valves 150 

Setting Valves of New Brown Engine 155 

Fly-wheel Governor 161 

Lubricator 163 

Crank Pin 163 



CONTENTS 



Chapter VI. 

PUMPS 166 

Single Steam Pump . . 167 

Setting Pump Valves 171 

Directions for Setting up and Operating 173 

Deane Duplex Steam Pump 177 

Mason Pump Governor 183 

Chapter VII. 

CONDENSERS 184 

Surface Condenser 184 

Jet Condenser 186 

Bulkley Condenser 190 

Vacuum 191 

Vacuum Gauge 193 

Chapter VIII. 

INDICATORS 194 

Leading Pulley 194 

Piston 195 

Cylinder . 196 

Coupling 196 

Springs 197 

Pantograph 205 

Planimeter 206 

Indicators . . . 210 

Defective Diagrams 219 

Horse Power . 227 

Chapter IX. 

HYDRAULIC ELEVATOR 239 

Chapter X. 

USEFUL INFORMATION 241 



CHAPTER I. 

BOILERS, 

Steam boilers are made in a variety of shapes, according 
to the types, uses, and conditions. The materials of which 
boilers are constructed are exposed to conditions which 
weaken them and shorten the life of the boiler. Among these 
conditions are corrosion, both external and internal, high 
pressure, and expansion and contraction, due to varying 
temperatures and pressure. Where exhaust steam returns 
to a boiler, oil with steam makes foam and the boiler is 
liable to bag. 

Question. — What are the different kinds of boilers? 

Answer. — Stationary, marine, locomotive. 

What are the different styles of boilers? 

Return tubular, marine, locomotive, upright, flue, and 
water tube. 

What is a steam boiler? 

A steam boiler is a closed vessel in which steam is gener- 
ated for power or heating purposes. 

What is a fire-tube boiler? 

Any boiler where the fire passes through the tubes. 

Describe a return tubular boiler. 

A return tubular boiler is a fire-tube boiler where the fire 
passes over the bridge wall under the boiler, returning through 
the tubes into the front connection and then to the chimney. 

What is the dry sheet? 

The dry sheet is in the front part of the boiler, is a part of 
the boiler shell, and its object is to form the bottom of the 
smoke-box. 



2 PRACTICAL STATIONARY ENGINEERING 

What is the usual diameter of return tubular boilers? 

Standard makes are from 24 to 72 inches. 

What is the usual length ? 

Standard makes are three times diameter. 

Where are the grates? 

The grates are at the front end of the boiler, and are about 
thirty inches from the shell. 

Are grates level? 

The grates pitch to the bridge wall 3 inches. 

How are they supported? 

By bearer bars. These bars are supported by the brick- work. 

What are the grates made of? 

The grates are made of cast iron. 

What kind of joints are used in a boiler? 

The boiler plate has lap and butt joints. These joints or 
seams may be either single or double or triple riveted. The 
seam running lengthwise is the longitudinal seam. The seam 
around the boiler is the girth seam, and is single riveted. 

What is the usual size of tubes in a boiler? 

In a return tubular boiler they are from 2 to 4 inches di- 
ameter. 

The tube sheets are drilled, reamed, and the burrs re- 
moved. The tubes are then fastened into the plate by ex- 
panding, which is done with a roller expander. The tube 
ends are then beaded or turned over, forming a tight joint 
between plate and the tube. 

Which way do the heads flange? 

The front head flanges out, so that it can be caulked. The 
back head flanges in. 

How are the heads protected? 

The back head is protected by water. The front head is 
protected by brick-work. 



How is the dry sheet protected? 

The dry sheet and rivets are protected by brick-work rest- 
ing on the arch of the fire-door. The brick-work goes under 
the boiler far enough to cover the first head row of rivets. 

What is the difference between a flush front and an over- 
hanging front? 

The front of a boiler may be a flush front or an overhang- 
ing front. The flush front must be protected by the brick- 
work. The overhanging front is used so that the dry sheet 
and the rivets need no protection from the fire, as it is out- 
side of the furnace. 

In an overhanging front boiler what protects the iron 
front? 

An 8-inch wall over the arch. 

What is the difference between a lap joint and butt joint? 

The lap joint is the lapping of two ends one over the other. 
The butt joint is the ends coming together, and a cover plate 
on the inside and one on the outside. 

Which is the wider cover plate ? 

The inner plate. 

Why is the inner cover plate the widest? 

To give strength to the caulking edge. 

Why is the girt seam single riveted? 

Because there is not so much surface on the heads of the 
boiler for the steam as on the sides. 

How are the tubes measured, inside or outside? 

Always on the outside. 

If tube ends leak, what should be done? 

Expand and bead them over. 

Is there any difference in the thickness of -the shell and 
heads of the boiler? 

In a return tubular boiler the heads are tf thicker than 



4 PRACTICAL STATIONARY ENGINEERING 

the shell in order to give it strength, on account of the many 
holes, for the tubes. 

If boiler was lying on the ground, could you tell which was 
the head? 

Yes, by the flange and dry sheet. 

How is the dry sheet protected ? 

In a flush-front boiler the brick-worK must go back far 
enough to cover up the rivets to keep them from burning 
out. 

Is the dry sheet a separate part of the boiler ? 

No, it is a part of the shell. 

With an overhanging front boiler, how is the cast-iron 
front protected? 

By two rows of brick built over the arch of the door. This 
is to keep the intense heat from cracking the boiler front. 

How is the boiler set ? 

The boiler has two walls on the sides and rear end, with 
an air-space of about three inches. This space is to allow for 
expansion of the inner wall without injuring the outer wall, 
and is to prevent radiation of heat. Bricks project across 
the air-space, but do not go into the outer wall. This is to 
keep the inner wall from collapsing. 

How thick are the walls ? 

The wall at the grate line, according to the Hartford set- 
ting, is 30 inches, the outer wall is 12 inches, the inner wall is 
16 inches with a 2-inch air-space. 

How thick is the bridge wall? 

At the base 28 inches. 

How far from the shell? 

From 8 to 12 inches. 

Where is the bridge wall ? 

At the back of the grates. 



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What is its use? 

To keep the coal on the grates and keep the flame up 
against the boiler shell. 

Where is the back connection? 

The back connection is at the back end of the boiler and 
the brick- work. 

Where is the closing-in line in the back connection? 

The closing-in line is about three inches above the upper 




Figure 4. 



row of tubes. There is \ inch space left for the expansion 
of the boiler. 

What supports the brick- work over the back connection? 

There are iron bars reaching from side to side. The bricks 
rest on these. 

Where is the blow-off pipe? 

A blow-off pipe should connect with the shell at the bottom 
near the rear head. The shell at this point is reinforced by 



PRACTICAL STATIONARY ENGINEERING 

of an inch thick, riveted to 
shell. 

Of what use is the blow-off pipe? 

The blow-off pipe is to drain the boiler. 

Where does the blow-off pipe lead to? 

The blow-off pipe leads out of doors or into a blow-off 
tank. 

When is it used? 

Every morning. This is because the sediment has a chance 
to settle to the bottom of the boiler over night. 

How large is the blow-off pipe? 

Usually 2 inches. 

What is a blow-off tank? 

A blow-off tank is about five feet deep and two and 
one-half to three feet in diameter, having a manhole in 
the top, and is used to blow off the boiler in. 

What pipes lead into the blow-off tank? 

The blow-off pipe from the boiler and all drips, and there 
is an overflow and a vapor pipe. The overflow leads to the 
sewer : the vapor pipe is to relieve the tank of pressure. 

When do you use a reinforcing piece on a boiler? 

When the pipe is over 1J inches in diameter, a piece of 
boiler plate is riveted to the shell. This is to give strength 
and a better hold to the threads. 

What is the best kind of a blow-off valve? 

Plug cock is the best kind of blow-off valve, as a globe 
valve would fill up with sediment and leak. This valve should 
be opened slowly and closed slowly. Stopping the flow of 
water quickly might burst the pipe at the elbow; and, if 
blow-off pipe should burst, immediately disconnect steam 
connection to other boilers, to prevent steam leaving these 
boilers. 



What kind of brick is used in the settings? 

Hard-burnt brick except around the fire-box, which is of 
fire-brick. These brick extend up to the closing-in line and 
beyond the bridge wall (every fifth course being a course 
of headers), which extends back to the rear of the bridge 
wall, and the wall is closed in upon the shell at a point one 
course of brick below the lugs. The face of the front wall, 
and both the face and top of the bridge wall, are lined with 
one course of fire-brick laid as headers. The rear wall of the 
setting is also lined with one course of fire-brick. 

What support the brick over the back connection? 

The brick over the back connection are supported either 
flat cast-iron plates or by arch bars; and these last are 
lined with fire-brick, which are held by projections on the 
ends of the bars. 

What care is taken in setting the boiler? 

In setting the boiler, great care should be taken that the 
weight of the boiler rests on the brackets, or lugs, and in no 
case on the cast-iron front. The brackets are so placed that 
their bearing surface are 3 or 4 inches above the centre of 
the boiler. Boilers up to 16 feet in length are furnished with 
4 brackets: those of greater length have 6 brackets. 

What do the brackets rest on? 

The front bracket should rest on the wall plate, and the 
others rest upon rolls. This is to provide for the expansion. 
All boilers expand when heated. 

Where are the fusible plugs placed? 

Fusible plugs are placed in return tubular boilers 3 inches 
above the upper row of tubes, in the back head. 

For what purpose? 

For a safeguard against overheating, should the water 
get low. 



10 PRACTICAL STATIONARY ENGINEERING 

Of what is the fusible plug made? 

The fusible plug is made of brass. The plug consists of an 
alloy of tin, lead, and bismuth, which melts at a low tempera- 
ture (360° F.). So long as the plug is covered with water, 
the plug is kept from melting, water taking out all the heat 
that the fire puts in; but, should the water sink low enough 
to uncover the plug, it quickly melts, and allows the 
steam and water to rush into the furnace, thus relieving the 
pressure. 

What are the differences in fusible plugs? 

Inside and outside; you can tell them by the shape of the 
cone-shape filling : the largest part is towards the pressure. 

Where is the combustion chamber? 

Back of the bridge wall. 

Does steam protect the fusible plug? 

Steam throws off heat instead of absorbing it. 

Water being as hot as the steam, why does not the fusible 
plug melt? 

The water absorbs all of the heat that the fire can put into 
the fusible plug. 

How are boilers kept clean? 

By putting in soda ash. Then the boiler should be fre- 
quently blown out, as the soda softens the scale. 

What kind of valves are put on the blow-off pipe ? 

A plug cock is the best kind of blow-off valve, as a globe 
valve is liable to get stopped up with sediment and leak. 

How should valves be opened when the boiler is under 
pressure ? 

All valves should be opened very slowly. 

Does the boiler set level? 

The boiler pitches to the rear about one inch. 

Where is the closing-in line of the boiler? 



BOILERS 11 

Where the brick-work touches the boiler and always below 
the water line. 

How do you get into the back connection? 

Through the back-connection door. 

Can you see the whole back head ? 

No, you can see the fusible plug, the ends of the tubes, 
blow-off pipe, hand-hole plate. 

Where are the hand-hole plates, and what are they for? 

The hand-hole plates are at each end of the boiler below 
the tubes. They are to clean out the boiler. 

What shape are they ? 

The hand-hole plates are oval, so they can be removed. 

Where is the manhole cover, and how large is it ? 

The manhole cover is on top of the boiler, 11 X 15 inches. 

Which dimension lengthways ? 

The short dimension, or 11 inches. 

What is the manhole frame made of? 

The manhole frame is made of pressed steel. 

Where are the nozzles, and what are they made of? 

The nozzles are on top of the boiler. They are made of 
cast steel. 

What does the furnace mouth consist of? 

The furnace mouth consists of a dead plate, two cheeks, 
and arch. 

Where is the feed-pipe? 

The feed-pipe runs along the front of the boiler above the 
fire-doors up and through the dry sheet, enters the boiler 
above the tubes, runs along to the rear, crosses, and discharges 
the water between the tubes and shell. 

How are boilers fed with water? 

E oilers are fed with a pump, inspirator, or by city pressure. 

Can you feed one boiler from another? 



12 PRACTICAL STATIONARY ENGINEERING 

One boiler can be fed by closing the main blow-off and! 
opening blow-off on each boiler, then water will equalize in. 
each boiler. 

Where are the nozzles, and what are they for? 

There are two nozzles on a boiler. The front nozzle, 
steam connection, should be made for the engine or build- 
ing. The rear nozzle is for the safety-valve. When but 
one nozzle, steam is taken from one side of safety-valve; the 
opposite side being used when the safety-valve opens to 
relieve the boiler pressure. 

How is the steam connection made to the boiler? 

The steam connection is made with a flange joint. 

Of what are the nozzles made? 

The nozzles are made of cast steel, and riveted to the shelh 

What are the different kinds of safety-valves ? 

There are two kinds, lever and ball, and spring. 

What are they for? 

The object of the safety-valve is to prevent the pressure 
going higher than a certain point. They should open when 
the pressure reaches that number of pounds, and then blow 
from the boiler all the steam the boiler can make without 
increasing the pressure. 

How do you increase the pressure? 

With the lever-and-ball type there is a ball which you 
move out toward the end of the lever, increasing the 
pressure; and moving in decreases the pressure. The pop, 
or spring, valve, tightening down on the spring, will give 
more pressure. This is adjusted by a ring inside of safety- 
valve. By removing a set screw on the side of valve, this 
ring can be reached. By turning up, blows back more; by 
lowering, blows back less. 

What care do you give a safety-valve ? 



BOILERS 13 

Safety-valves should be tested by lifting the lever of the 
valve or pulling down on the lever of the pop- valve, and 
steam will blow out. 

Should there be any valves between the safety-valve and 
the boiler? 

There should be no valve connected with the safety-valve 
whatever. 

Will the safety-valve close at the same pressure that it 
opens? 

Pop-valves do not close at same pressure they open at, 
blowing back several pounds before closing. 

If safety-valves stick and pressure runs too high, what do 
you do? 

If pressure runs too high, open fire-doors and close ash-pit 
doors, cover fires heavy with coal, open valve slowly, that 
will release boiler of steam pressure until pressure comes down 
to where it should blow at, then try the safety-valve. 

Would you start the pump, if not running ? 

I would not start the pump nor open the safety-valve. 

If you had a battery of boilers and the safety-valve should 
stick on one boiler, would the pressure rise in that boiler? 

Pressure could not rise higher on that boiler when con- 
nected with other boilers, because pressure would equalize 
through the main steam pipe. 

How do you test a safety-valve? 

In testing a safety-valve to see if large enough, it may be 
made by shutting all steam valves and see if pressure does 
not go above blowing point. 

Are there any valves on the feed-pipe? 

On each feed-pipe is a check-valve to prevent the water 
backing out of the boiler. 

Are there any other valves on the feed-pipe? 



14 PRACTICAL STATIONARY ENGINEERING 

There is a stop-valve between the check-valve and the 
boiler. 

In a battery of boilers, is there more than one check-valve? 

Each boiler has a check-valve and a stop-valve. 

What is the stop-valve for? 

The stop is to regulate the water-feed, and is closed if the 
check-valve needs to be repaired. 

If check-valve should leak, would the water leave -the 
boiler? 

Water could not pass beyond the pump. 

What kind of a pipe is best for a feed-pipe? 

A brass pipe is best because it does not corrode. 

Can you feed one boiler from another? 

Yes, by closing main blow-off. Open the blow-off to each 
boiler, the water will equalize in all of the boilers. 

What makes a check-valve rattle? 

When the pump is not pumping steady. 

How would you know if the pump was pumping steady? 

By opening the pet cock on the air chamber, you would 
get a steady flow of water. If the pump was not pumping 
steady, you would get water and then steam, and you might 
hear the check-valve rattle. 

What is a fire-box boiler? 

A fire-box boiler is where the fire is on the inside, like 
a water-leg boiler, a common upright, "Manning" and 
"Deane" boilers, also locomotive boilers. 

Describe a return tubular boiler. 

Return tubular boilers are externally fired, the fire passing 
over the bridge wall, under the boiler, returning into the 
tubes to the uptake or smoke-box. The diameter of the 
boiler varies from 36 inches up to 72 inches, and the length 
is three times the diameter. The joints are single or double 



BOILERS 15 

riveted. The seam around the boiler is usually single 
riveted. The tubes are about three inches in diameter, ex- 
panded into the head and beaded over. In the front end of 
the boiler the dry sheet forms the bottom of the smoke-box. 
It is a part of the boiler shell, and is protected from the fire 
by brick-work beneath it. This brick-work extends under 
the boiler just beyond the first row of rivets. If the brick- 
work falls down, the dry sheet and rivets would be burned. 
In a flush-front boiler the dry sheet must be continually pro- 
tected. In an overhanging front the sheet is outside, and 
overhangs the iron front. The dry sheet is outside of the 
setting, and needs no special protection from the fire. This 
is why it is used. 

The walls of the back setting are about two feet thick. The 
wall consists of two walls, with an air-space between each 
wall. The boiler is held up in the brick-work by cast-iron 
lugs riveted to the shell, two on each side. These lugs rest 
on cast-iron plates in the brick-work. The closing-in line is 
where the brick-work closes in to the boiler, half-way up 
each side. If the fire went clear around the shell, the upper 
part would burn out where' the steam-space is. The grates 
are at the front end, about two feet below the bottom of the 
boiler. They are of cast iron. The bridge wall is back of 
the grates. It is to keep the flame against the shell and 
prevent coal falling over into the combustion chamber. The 
combustion chamber is back of the bridge wall. The back 
connection is between the end of boiler and the back brick 
wall. You can get into it through a door at the back end 
of the boiler or over the bridge wall. You cannot see the 
whole of the boiler head, as it is bricked in from 2 to 3 
inches above the tubes*. This brick-work is put in to protect 
the end of the boiler at the steam-space. The boiler has a 



16 



PRACTICAL STATIONARY ENGINEERING 



cast-iron front to which the furnace doors, ash-pit doors, and 
tube doors are attached. 

What can you see in the back connection? 

In the back connection can be seen blow-off pipe, tube 
ends, fusible plug, and hand-hole plates. 




Figure 5. 



BOILERS 17 

What are tubes made of? 

Boiler tubes are made of steel or wrought iron, most com- 
monly of charcoal iron, and lap welded. In the formation of 
the lap the plate is upset, then bent around until the thick- 
ened edges lap sufficiently. It is then heated successively, 
about eight inches at a time, and welded over a mandrel. 
Tubes are measured by their outside diameters, and are 
usually true to gauge, so that holes for them may be bored 
without taking measurements from the tubes. 



UPRIGHT BOILERS, 

What is an upright boiler? 

An upright boiler is a fire-tube boiler. It has a fire built 
in a fire-box inside the boiler. The grates are at the bottom 
of the boiler, on an iron ring. Around the fire is an internal 
shell, which forms a space, or water leg, between the fire 
and the outer shell. This space is 3 inches or more, and is 
always filled with water. Directly over the fire is a tube 
sheet, filled with tubes 2 inches in diameter. These tubes 
run to the top of the boiler, into the upper tube sheet. The 
smoke then passes into a smoke bonnet and flue. The 
inner shell extends from the mud ring to the lower tube sheet. 

What is a mud ring ? 

The mud ring is a cast-iron ring which forms the space 
between the outer and inner shell at the bottom of the boiler. 

Are there any braces in an upright boiler? 

There are stay-bolts running from the outside shell to the 
inside shell through the water leg. These bolts are threaded 
their entire length, and are screwed in, then cold-headed: 
these are to prevent the inner shell from collapsing. 

How is the water leg cleaned? 



18 PRACTICAL STATIONARY ENGINEERING 

There are two or more hand-hole plates at the bottom of 
the water leg, and three on a level with the lower tube sheet. 

Where is the feed-pipe? 

The feed-pipe enters at the lower part of the water leg. 
These boilers are carried about three-quarters full of water. 

Where is the steam pipe? 

The steam pipe is taken from the top head. 

Where is the blow-off pipe? 

The blow-off pipe is in the bottom of the water leg. 

Where is the fusible plug? 

The fusible plug is generally found in the lower tube 
sheet, but should be placed about seven inches below the water 
glass in a tube. This plug is put in through a hole in the 
outside shell with a socket wrench. 

Stay-bolts are put in water legs of upright or locomotive 
boilers, to stay any flat or round surfaces from collapsing. 

They are about j-inch diameter. A J-inch hole is some- 
times drilled in the outer end, just beyond the shell, to show 
if stay should break. Stay-bolts get corroded, and break 
near the outer shell. They are 5 to 10 inches apart, accord- 
ing to pressure carried. 

Upright boilers can bag on the lower tube sheet, and on 
the inside sheet between the stay-bolts. 

To inspect an upright boiler, look for leaks on tube ends 
top and bottom, for cracks between tubes on tube sheet, 
for leaks at seams. Sound the stay-bolts with a hammer to 
see if broken. Look for corrosion around grates on inside 
shell, and see if not blistered or bagged. 

Some upright boilers have the head submerged beneath 
the water. 

Are the heads of a boiler as thick as the shell? 

The head or tube sheet is usually made jq inch thicker 



BOILERS 19 

than the shell plate. This is done for additional stiffness 
and increase of strength, the plates being weakened by 
drilling the holes for the ends of the tubes. Tubes should 
be arranged in vertical and horizontal rows, if possible, 
in order that the rising bubbles of steam may not be hin- 
dered. The tubes should be from | to 1 inch apart, and the 
bottom tubes 6 inches from the shell. 

How do you brace the head of a boiler? 

The bracing of the heads of return tubular statioDary 
boilers, when the diameter is less than 60 inches, is accom- 
plished by using diagonal braces, one end of each being 
riveted to the shell and the other bolted to a tee-bar which 
is fastened by rivets to the head. The tee-bars are laid 
out according to the customary practice. 

How do you brace the head of a 60-inch boiler? 

When the diameter is 60 inches or over, through bolts 
are employed, running from head to head, with two nuts 
on each end, one on the outside and one inside the plate. 
At the points where the bolts pass through the plate, the 
head is stiffened by channel iron bars, one continuous bar 
being used for each horizontal row of bolts. In some cases 
a combination of through bolts and diagonal braces is em- 
ployed. 

How do you attach pipe to the outside shell ? 

When pipes 1| inches are attached to the outside shell 
of the boiler, the metal is thickened by a reinforcing plate, 
which is secured by rivets. 

For main connection of steam pipe and safety-valve, 
nozzles are provided, which are riveted to the shell, the face 
of the outer flange being turned, and the flange itself drilled 
for the reception of bolts. 

An ash-cleaning door is provided in the rear wall. 



20 PRACTICAL STATIONARY ENGINEERING 

The upper shell of the boiler may be covered with one 
course of fire-brick laid on edge or with non-conducting 
covering. 

What are the different kinds of braces in a boiler? 

There is the radial brace, crowfoot, through brace, and 
gusset brace. 

Are through bolts or braces the same diameter throughout ? 

Through braces are always larger at the ends, the depth of 
the threads, so that the strength will be equal throughout. 

What does the number of braces depend upon? 

The number of braces depends upon the area to be braced, 
steam pressure carried, size of braces. 

What is the size of through braces ? 

Usually 1 inch to If . 

What is a gusset stay ? 

This stay consists of a wrought-iron or steel plate secured 
to the heads and shell by either angle or T iron. It is much 
used for staying the heads of internally fired boilers of the 
Lancashire and Galloway type. 

The method in which the gusset plate is flanged to one 
side and the angle iron riveted to the other. Gusset stays 
are placed radially in a boiler, the largest one in the centre, 
and smaller ones to the right and left of it. 

What does the through brace pass through before going 
through the head? 

There is a channel iron or angle irons riveted to the head 
on the inside. This is to give strength to the heads which 
the through braces pass through. 

What is a palm brace? 

The middle brace would come under the manhole; and, to 
prevent this, one end is radial. The end that comes through 
.the head is fastened like a through brace, and the other end 



BOILERS 21 

is flattened and riveted to the shell with 3 rivets near the 
manhole. This is called a "palm brace." 

Water Column. 

What is the water column for? 

The water column is used to ascertain the height of the 
water in the boiler. 

Where is it placed? 

The water column is placed at front end of the boiler, con- 
nected to the top and bottom by pipes. The lower nut on 
the gauge glass should be 3 inches above the upper row of 
tubes. This you can tell by opening the tube-sheet door and 
sighting across. 

What if you find it is too low ? 

Would carry water proportionately as high in the glass. 

If glass should break, what valve would you close 
first? 

If the gauge glass should break, would close the lower 
valve first, as the water would flow out to that point. This 
gauge is liable to break at all times. For this reason it is es- 
sential, when leaving the boiler at night, to close the gauge- 
glass valves. You should blow this out every morning, top 
and bottom, before starting up. 

If you close the top valve on the gauge, what is the effect 
on the water? 

The water will rise to top almost instantly. 

What if you close the bottom valve? 

Water will remain where it is. 

If you shut the top valve and the water does not rise, what 
is the reason? 

The lower valve may be closed or the valve may leak. 



22 



PRACTICAL STATIONARY ENGINEERING 



If the glass is full of water and the gauge-cocks do not show 
water, what is the reason? 

This shows that it is closed on top. 

If at any time you could not get steam or water from the 
column? 

This shows that both valves are closed or stopped up. 



To S 




Figure 



Suppose some morning we see water in the glass, we try 
the cocks and get no water, what is the reason ? 

This shows that there is a vacuum in the boiler. Open 
gauge-cocks above water line, let air in, water will flow out. 



BOILERS 23 

How can you tell if the gauge glass and water column is 
all right by looking at it? 

You could see a slight motion of the water in the glass. 

What would you do if you found the water too low? 

Bank fires heavy, close ash-pit doors, cool boiler off. 

Would you start the pump at that time? 

No, it would be very dangerous to do so before the boiler 
was cool. 

Would you lift the safety-valve? 

No, that would be dangerous. The water might flash 
into steam and cause the boiler to explode. 

BABCOCK AND WILCOX BOILER. 

These boilers are composed of lap-welded wrought-iron 
tubes, placed in an inclined position and connected with 
each other, also with a horizontal steam and water drum by 
vertical passage at each end, while a mud drum is connected 
to the rear and lowest point in the boiler. 

The tube ends are expanded into vertical headers made of 
cast steel. The vertical headers are connected to the steam 
drum by nipples, one header for each vertical row of tubes, 
and are of such form that the tubes are staggered, or so 
placed that each row comes over the spaces in the previous 
row. 

The holes are accurately sized, made tapering, and the 
tubes fixed therein by an expander. The section thus formed 
is connected with the drum, and with the mud drum also by 
short nipples expanded into the bored holes. The openings 
for cleaning opposite the ends of each tube are closed by 
hand-hole plates. The joints are made in the most thorough 
manner by milling the surfaces to accurate metallic contact, 



24 PRACTICAL STATIONARY ENGINEERING 

and are held in place by wrought-iron forged clamps and 
bolts. 

The steam and water drum is made of flanged steel of 
extra thickness and double riveted. They can be made for 
any desired pressure, and are always tested at 50 per cent, 
above the pressure for which, they are constructed. The 
mud drum is of cast iron, as the best material to withstand 
corrosion. In the mud drum are three common hand-hole 
plates for cleaning. 

Why is the water- tube boiler used? 

The water-tube boiler is used for additional safety at high 
pressure and for quick steaming. Only a small part can 
burst at a time. 

Are there any braces in a Babcock and Wilcox boiler? 

There are no braces. The forged-steel drumheads are 
spherical, therefore do not need bracing. 

Where is the manhole plate? 

Manhole is in the front head. 

What can you see inside of the steam drum? 

You can see the feed-pipe, the dry pipe, the baffle plate, 
and a pipe from the lower connection of the water column 
and the fusible plug which is about four inches up on the 
side of the drum over the fires. 

What is a water-tube boiler? 

Water in the tubes and the fire outside. 

What is the method of supporting the boiler? 

The usual method is to hang the boiler from wrought-iron 
girders resting on vertical iron columns. The brick-work 
is not depended upon as a means of support. The bridge 
wall is built up to the bottom row of tubes. Another fire- 
brick wall is built between the top row of tubes and the 
drum. These walls and baffle plates force the hot furnace 



BOILERS 



25 



gases to follow a zigzag path back and forth between the 
tubes. The gases finally pass through the opening in the 
rear of the wall, into the chimney flue. 

Where is the water column? 

The water column is at the front of the steam drum. In 
the lower connection there is a pipe extending into the 
drum about four feet, in the upper connection the pipe leads 
into the dry pipe. 

Where is the blow-off pipe? 

The blow-off pipe is in the mud drum. 

Where is the feed-pipe? 

The feed-pipe is in the steam drum, front or rear head. 

What is the standard evaporation per horse power? 

The standard of steam boiler horse power as adopted by 
the American Society of Mechanical Engineers rates a com- 
mercial horse power on an evaporation of 30 pounds of 
water per hour from a feed-water temperature of 100° F. 
into steam at 70 pounds' gauge pressure. 

An approximate list of square feet of heating surface per 
horse power for difference in styles of boilers. 



Square Feet Coal per Square 



Type of Boiler. 

Water tube 

Tubular 

Flue 

Plain cylinder .... 

Locomotive 

Vertical tubular . . . 



leating Sur- 


Feet H. P. 


Relative 


s for 1 H. P. 


per 


Hour. 


Economy. 


10 to 12 




3 


100 


10 to 12 




.25 


.91 


8 to 12 




.4 


.79 


6 to 10 




.5 


.69 


12 to 16 




.275 


.85 


15 to 20 




.25 


.80 



26 PRACTICAL STATIONARY ENGINEERING 



HEINE BOILER. 

Inside of the shell is located the mud drum, 2 or 3 inches 
above the bottom of the shell. 

It is thus completely immersed in the hottest water in the 
boiler. 

It is of oval section, slightly smaller than the manhole, 
made of strong sheet iron with cast-iron heads. 

It is entirely enclosed except about eighteen inches of its 
upper portion at the forward end, which is cut away nearly 
parallel to the water line. 

The feed-pipe enters it through a loose joint in front. 
The blow-off pipe is screwed tightly into its rear head, and 
passes by a steam-tight joint through the rear head of the 
shell. 

Just under the steam nozzle is placed a dry pipe. 

A deflection plate extends from the front head of the shell, 
inclined upwards, to some distance beyond the mouth or 
throat of the front water leg. It will be noted that the 
throat of each water leg is large enough to be the practical 
equivalent of the total tube area, and just where it joins the 
shell it increases gradually in width by double the radius of 
the flange. 

In setting the boiler, place its front water leg firmly on 
a set of strong cast-iron columns, bolted and braced together 
by the door-frames, dead plate, etc., and forming the fire 
front. This is the fixed end. The rear water leg rests on 
rollers which are free to move on cast-iron plates firmly set 'in 
the masonry of the low and solid rear wall. 

Wherever the brick- work closes into the boiler, broad joints 
are left, which are filled in with tow saturated with fire clay, 



BOILERS 27 

or pliable material. Thus the boiler and its walls are each 
free to move separately during expansion or contraction. 

On the lower and between the upper tubes are placed light 
fire-brick tiles. The lower tier extends from the front water 
leg to within a few feet of the rear one, leaving there an up- 
ward passage across the rear end of the tubes for the flame. 
The upper tier closes into the rear water leg and extends 
forward to within a few feet of the front one, thus leaving the 
opening for the gases in front. 

The bridge wall is hollow, and has small slotted openings in 
the rear to deliver hot air into the half-consumed gases which 
roll over the bridge wall into the combustion chamber. 
It receives its air from channels in the hollow side walls. 



STEAM GAUGE. 

What is the steam gauge for? 

Steam gauge indicates the pressure of the steam contained 
in the boiler. The most common form is the Bourdon press- 
ure gauge. It consists of a tube, of elliptical cross-section, 
which is filled with water and connected at end with a pipe 
leading to the boiler. The other end is attached to a link, 
which in turn is connected with a sector. This rack gears 
with a pinion to which is attached the index pointer. 
When water in the elliptical tube is subjected to pressure, the 
tube straightens out, the movement of the free end is trans- 
mitted to the pointer by the link, and the pressure is recorded 
on the graduated dial. 

In connecting up the steam gauge, place a coil or bend in 
pipe below the gauge. This fills with water from condensed 
steam. This is to protect the gauge from heat, which protects 
the spring from being injured by the heat of the steam. 



28 PRACTICAL STATIONARY ENGINEERING 

Where is it placed? 

It can be placed where one may wish, sometimes on the 
water column. If it is above the boiler and steam has to hold 
up a column of water, it will not register as much as the boiler 




Figure 7. 

Showing Some of the American Steam Gage and Valve 

Company's Gauges. 

pressure by 1 pound for every 2 feet of water supported. 
If gauge is below the steam pipe, it will register more by 1 
pound for every 2 feet of water head. 



BOILERS 29 

If gauge was placed on the water column and you should 
close top valve, would it register? 

Steam gauge would still register, getting its pressure from 
the lower connection. 

What is meant by setting the hand on the steam gauge at 
zero ? 

This means that the gauge is set at atmospheric pressure, 
14.7 pounds. 

How is a steam gauge tested ? 

Steam gauges are tested by comparing with a test gauge, 
being connected to a small hydraulic hand pump to get the 
pressure. 

What is inside of a steam gauge? 

A hollow spring. 

Can a steam gauge get out of order? 

A steam gauge may not register right. First, spring might 
leak; second, spring might be broken; third, vacuum in the 
boiler, the hands resting against the pin, and the spring 
pulling it makes the hands slip on the spindle and causes it 
to register light. 

If you had a high pressure of steam in the boiler and 
water out of sight, would it be safe to raise the safety-valve 
to let out the steam? 

No, under no circumstance. 

What might happen if you have vacuum in your boiler? 

When there is vacuum in the boiler, the hand rests against 
pin, and the spring pulling on it makes hand slide on the 
spindle and causes it to register light. 

How do you know if it registers correctly? 

To set the gauge on the boiler, set it at zero with no pressure 
on the boiler. See that it agrees with the safety-valve, or set 
it with another gauge that is known to be right. 



30 PRACTICAL STATIONARY ENGINEERING 

How do you know if the steam gauge is correct ? 
If the steam gauge and safety-valve do not agree, the 
steam gauge may be out of order. 



FIRES. 

What is the first duty of the fireman? 

Upon going to work, he should examine the water level. 
The gauge-cocks should be tried: the gauge glass is not 
always reliable. In a battery of boilers the gauge-cocks on 
each boiler should be tried. Some serious explosions have 
resulted from the fact that the fireman only consulted the 
water level in the first boiler, and took it for granted that the 
level in the other boilers was the same. 

If the water is discovered to be low, quickly cover the 
fires with ashes, or, if not convenient, with fresh coal. Do 
not turn on the feed, and do not tamper with the safety- 
valve or any other steam outlet. 

What would be the proper method to start a fresh fire ? 

First cover the grate bars all over with fresh coal, then put 
the wood on the top of the coal. Start the fire with kind- 
lings, leaving the furnace door open until the wood is well 
ablaze, then add more coal as required. 

How do you bank a fire over night ? 

With a hoe push back the upper half of the fire, leaving the 
clinkers and ashes on the grate, then pull the ashes out with 
the hoe, and then cover with fresh coal, leaving part of the 
grates bare. 

How do you clean a soft-coal fire? 

Let one side burn down, build up the other side, pull the 
burnt side out. Then throw over the good fire onto the 
clean grates with slice bar or a hoe, and build up that side, 



BOILERS 31 

allowing the other to burn down, then pull second side, and 
spread the fire over evenly. 

How do you clean a hard-coal fire ? 

Shove good coal back to bridge wall and pull out ashes 
and clinkers at front. Pull good coal forward and pull 
clinkers over the fire from the back. 

Spread over evenly. Soft-coal fires may be broken up 
considerably with a slice bar, but hard coal cannot be 
broken up, but fires are kept clean by running slice bar 
underneath it. Before cleaning, see that there is plenty of 
water in the boiler and steam pressure is high, so you will 
not have to pump water in the boiler immediately after 
cleaning fires. 

The reason being that having the fire-doors open, reducing 
the body of fire under the boiler, putting on green coal, and 
then being obliged to put in cold water would cause too great 
a drop in the pressure. 

How thick are the fires? 

The thickness of the fires depends on the draft. With a 
very heavy draft a much thicker fire must be carried. A 
fire too thick for the draft blows back at the fire-door. The 
fires vary from 7 to 15 inches in thickness. In firing, feed 
often and light, placing coal on the thinner spots. When 
draft is poor, a thinner fire must be carried. If safety-valve 
blows, close ash-pit door. 

How do you connect boilers together? 

See that the water level is the same in each boiler, and 
that the steam pressure is equal in each boiler. Open valve 
slowly. 

What would you do in taking charge of a plant? 

In taking a new plant, I would look over all pipes leading 
to and from the boiler, look over water column to see that 
it is in the right position, also the safety-valve. 



32 PRACTICAL STATIONARY ENGINEERING 

How do you clean the tubes of a boiler? 

Most common is a tight-fitting scraper on a rod, which is 
run through the tubes or a jet of steam blown through 
them. I should recommend cleaning every day. This to 
be done when there is little demand for steam. At noon- 
time is best. 

CORROSION. 

What is corrosion? 

Corrosion may be defined as the eating away or wasting 
of the plates, due to the chemical action of impure water. 
It is probably the most destructive of the various agencies 
which tend to shorten the life of the boiler. Corrosion is of 
two forms, internal and external. Internal corrosion may 
present itself as: 1. Uniform corrosion; 2. Pitting or honey- 
combing; 3. Grooving. Corrosion is a general rusting or 
thinning of the plates. 

In cases of uniform corrosion large areas of plate are 
attacked and eaten away. There is no sharp line of division 
between the corroded part and the sound plate, and often- 
times the only way of detecting the corrosion is to drill a hole 
through the suspected plate and thus ascertain its thickness. 
Corrosion often violently attacks the stay-bolts and rivet 
heads. 

What is pitting? 

Pitting and honeycombing are readily perceived. The 
plates are in spots indented with holes and cavities from 
^2 to I inch deep. 

What is grooving? 

Grooving is generally caused by the buckling action of the 
plates when under pressure. Thus the ordinary lap joint of 
& boiler distorts the shell slightly from a truly cylindrical 



BOILERS 33 

form, and the steam pressure tends to bend the plate at the 
joint. This bending action is liable to start a small crack 
along the lap, which, being acted upon by corrosive agents 
in the water, soon deepens into a groove. The marks made 
along the seam by the sharp caulking tool, when used by 
careless workmen, is almost certain to lead to grooving. 

What is external corrosion? 

External corrosion frequently attacks boilers, particularly 
those set in brick-work. v The causes are dampness, exposure 
to weather, leakage from joints, moisture arising from the 
waste pipes or blow-out. When leakage occurs in a joint 
which is hidden by the brick-work setting, the plates may be 
corroded very seriously without being discovered. 

External corrosion should be prevented by keeping the 
boiler shell free from moisture and by repairing all leaks 
as soon as they appear. 

What is the effect of oil or grease in a boiler? 

Oil or grease often causes more trouble in boilers than scale 
or mud, and is much more difficult to remove, as it cannot 
be blown off. It requires special care where a part or the 
whole of the feed water comes from condensers or from heat- 
ing coils where exhaust steam is used. 

OIL OR GREASE. 

The action of oil or grease in a boiler is peculiar, but not 
more so than we might expect. It does not dissolve in the 
water nor does it decompose, neither does it remain on top 
of the water, but it seems to form itself into what may be 
described as slugs, which at first seem to be slightly lighter 
' than the water, of such a gravity, in fact, that the circulation 
of the water carries them about at will. After a short season 



34 PRACTICAL STATIONARY ENGINEERING 

of boiling these slugs or suspended drops seem to acquire a 
certain degree of stickiness, so, when they come in contact 
with the shell and flues of the boiler, they begin to adhere 
thereto. Then, under the action of heat, they begin the proc- 
ess of varnishing the interior of the boiler. The thinnest 
possible coating of this varnish is sufficient to bring about 
overheating of the plates, as we have found repeatedly in 
our experience. We emphasize the point that it is not neces- 
sary to have a coating of any appreciable thickness to cause 
overheating and bagging of plates and leakage at seams. 

Remember this : — 

The time when damage is most likely to occur is after the 
fires are banked, for then, the formation of steam being 
checked, the circulation of water stops, and the grease thus 
has an opportunity to settle on the bottom of the boiler and 
prevent contact of the water with fire sheets. Under these 
circumstances a very low degree of heat in the furnace is 
sufficient to overheat the plates to such an extent that 
bulging or bagging is sure to occur. When the facts are 
understood, it will be found quite unnecessary to attribute 
the damage to low water. 

This is almost certain to be the result of grease in a steam 
boiler. It settles down on the fire sheets when the draft is 
closed, and the circulation of water nearly stops, and prevents 
contact between the plates and the water. As a consequence, 
the plates over the fire become overheated; and under such 
circumstances a very slight steam pressure is sufficient to 
bag the sheets. Unless the boiler is made of very good ma- 
terial, the plate is apt to be fractured, and explosion is likely 
to occur. 

What is a bag ? 

A bag is caused by oil, grease, or any sediment collecting on 



BOILERS 35 

the bottom of the shell over the fire. Keeping the water away 
from the shell, allowing the shell to become red-hot, the in- 
ternal pressure of the boiler forces the red-hot shell out, and 
necessarily follows a bag. 

If your boiler bags, what do you do ? 

If the bag is small, it is heated and forced back: if the. 
bag is large, it is cut out and a hard patch put on the in- 
side by rivets. 

BLISTERS. 

What is a blister? 

A blister is a separation of a thin layer of the sheet which 
peels off. 

What do you do if boiler blisters? 

Trim it off to the solid sheet; but, if large and half-way 
through the plate, patch it by putting a piece of boiler plate 
on the outside with tap-bolts. This is called a soft patch. 

What is the cause of a blister? 

It is caused by grease and sediment gathering on the 
shell. It becomes overheated, thus causing a thin layer of 
iron to peel off. 

Why is a blister dangerous, also a scaly boiler? 

A blister as well as scaly boilers will always cause an 
explosion by allowing the sheets to become red-hot, burnt, 
and also weakened. An untrue steam gauge is very dan- 
gerous, or a safety-valve that is stuck to the seat. 



36 PRACTICAL STATIONARY ENGINEERING 

FOAMING. 

What is foaming? 

Foaming is induced in stationary boilers by a filthy con- 
dition, particularly in this to which the feed water is supplied 
through open heater in consequence of oil or grease, dirty 
water being carried over with the exhaust steam into the boiler. 

What causes foaming? 

Foaming is induced in all boilers by the want of proper 
proportions between the water space and steam room in the 
boiler to supply the cylinder. 

How can you tell if the boiler is foaming? 

You can hear the water boiling very violently, gauge- 
cocks will first give water and then steam, bubbles will be 
chasing up through the glass, the engine pounds by water 
getting into the cylinder of the engine. 

What is the first thing to do, if boiler is foaming? 

The first thing to do is to find the water level. By opening 
the furnace door, closing damper doors, and covering the 
fires with coal or ashes, and shutting the main steam valve. 
When water level is found, blow off through the blow-off 
pipe and feed fresh water at the same time, and at the first 
chance to shut clown the boiler should be thoroughly cleaned 
inside. 

What is priming? 

Priming is due to a very large demand for steam from 
the boiler which lifts the water from the sheets. Priming 
is understood by engineers to mean the passage of water 
from the boiler to the steam cylinder in the shape of spray 
instead of vapor. It may go unseen, but it is generally made 
manifest by the white appearance of the steam as it issues 
from the exhaust pipe. Saturated steam, or steam contain- 



BOILERS 37 

ing water, has a white appearance, and descends in the 
shape of mist, while dry steam has a bluish color, and floats 
away in the atmosphere. 

Priming is generally induced by a want of sufficient steam 
room in the boiler, the water being carried too high or the 
steam pipe being too small for the cylinder, which would 
cause the steam in the boiler to rush out so rapidly that 
every time the valve opened it would induce a disturbance, and 
cause the water to rush over into the cylinder with the steam. 

How could a boiler foaming cause an explosion? 

It raises the water from the heated sheets, the sheets 
become hot, the water falls back, causing it to crack, and 
sometimes causing an explosion. 



STAYING. 

When under steam, a cylindrical shell is strained by in- 
ternal pressure in two directions, namely: transversely by a 
circumferential strain due to the pressure tending to burst 
the shell by enlarging its circumference, and longitudinally 
by the pressure on the ends. If a boiler were spherical, it 
would require no stays, because a sphere subjected to internal 
pressure tends to enlarge, but not to change its shape. All 
flat surfaces in boilers must be stayed, otherwise the internal 
pressure would bulge them out and tend to make them 
spherical in shape. The ends of steam drums on high- 
pressure water-tube boilers are often made hemispherical. 

The first and most important point in staying is to have 
a sufficient number of stays, so that they will entirely support 
the plate without regard to its own stiffness. The second 
is to have them so placed as to present the least obstructions 
to a free inspection and to have them so arranged as to allow 



38 PRACTICAL STATIONARY ENGINEERING 

a free circulation of water. Too much care cannot be taken 
in fitting stays and braces, as they are out of sight for long 
periods and a knowledge of their exact condition is not always 
easily obtained. 

In the ordinary fire-tube boiler the principal surfaces 
stayed are the flat ends, crown sheet, flat sides of locomotive 
boilers, and combustion chambers of cylindrical marine boilers. 

The most common and simple form of stay is a plain rod. 
It is used to stay the flat ends of short boilers. This stay 
is a plain rod passing through the steam-space, and has the 
ends fastened to the heads. The ends are fastened and the 
length adjusted in a number of ways, the simplest being 
nuts on both sides of the plate, and a copper washer strength- 
ens the plate and prevents abrasion by the nut. Stays are 
usually from f inch to If inches in diameter, and are made 
of wrought iron or steel, with an allowable stress of 7,000 
pounds per square inch. 

If a boiler is long (that is, more than 20 feet long), stays 
would sag in the middle and not take up the full stress in the 
end plates. For long boilers, gusset and diagonal stays are 
used. 

BOILER EXPLOSIONS. 

What is the cause of boiler explosions? 

Boiler explosions are, in nearly all cases, due to this 
cause, over-pressure of steam, — either the boiler is not strong 
enough to safely carry its working pressure or else the 
pressure has been allowed to rise above the usual point 
by the sticking or overloading of a safety-valve; or some 
similar cause. 

A boiler may be unfit to bear its working pressure for any 
of the following reasons: defect in design, defects in work- 



BOILERS 39 

manship or material, corrosion, wear and tear; misman- 
agement in operation. 

Defects of workmanship and faulty material may include 
the careless punching and shearing of the plates, burnt and 
broken rivets, plates burnt or otherwise injured in flang- 
ing, bending or welding, scoring of plates along the joints 
by sharp caulking tools, and injury of the plates by the reck- 
less use of the drift pin. Old plates may be injured in 
patching them with new plates, by the operation of removing 
the old rivets and putting in the new ones, and by the greater 
expansion and contraction of the new plate when exposed 
to the fire. 

Overheating may be caused by incrustation, or grease 
may lead to the formation of pockets. When the plate is 
covered by a heavy scale, the heat is not carried away by 
the water fast enough to prevent a rise of temperature, the 
plate becomes red-hot and soft, and yields to the steam 
pressure, forming a pocket; and, if the pocket is not discov- 
ered and repaired, it stretches, until finally the material be- 
comes too thin to withstand the steam pressure, the pocket 
bursts, and an explosion follows. 

The strength of the shell may be weakened by corrosion, 
pitting, and grooving. In some boiler explosions the plates 
have been found wasted to little more than the thickness 
of paper. 

Fractures which ultimately end in explosions may be 
produced by letting the cold feed water come directly into 
contact with the hot plates. The feed should be intro- 
duced into the coolest part of the boiler. 

Vertical boilers hold the first place in the list of those 
liable to explosions. The end of the tubes and the crown 
sheet are very liable to corrode. The crown sheet bulges 



40 PRACTICAL STATIONARY ENGINEERING 

downwards, and the reaction of the escaping steam may 
throw the boiler high in the air. Explosions may be the 
result of the collapse of the upper end of the tubes, — an 
event which may occur when the tubes pass up through the 
steam-space. 

Explain the cause of a boiler exploding. 

It is caused by the plates that are in contact with the 
fire-box or shell becoming overheated as the circulation 
is stopped after the steam is shut off, and as soon as 
the valve is opened the pressure is lessened and the water 
on the overheated sheet flashes into steam, and, if the 
boiler is not strong enough, a terrific explosion is the result. 

Opening the steam valve quickly to start the engine 
after the circulation in the boiler has stopped and the en- 
gine has been standing for a short time causes the boiler 
to explode. 

If you had a high pressure of steam in the boiler, and 
water out of sight, would it be safe to raise the safety-valve 
to let out the steam? 

No, under no circumstance. 

Why not? 

It would cause the water to rise, and, when the valve 
closed, the water would drop back on the heated shell and 
be liable to explode the boiler. 



INSPECTION AND TESTING BOILERS, 

First let fire die down, close ash-pit doors, open fire-doors, 
and, when boiler ceases to make steam, disconnect from other 
boilers. See that water head is kept up. The boiler should 
be left to cool twelve hours or more before blowing off. Then 
remove manhole cover, also hand-hole plates. Clean off 



BOILERS 41 

grates, ash-pit, back connection, then wash out the boiler 
inside with a hose. Get inside of boiler, and look along the 
seams for grooving, corrosion, or incrustation. Inspect the 
interior for broken stays or rivets or fractured joints. The 
condition of the plate is determined by tapping the plate 
with a hammer. Any weakness will immediately show itself. 
See that the feed-pipe is not clogged up, also that the fusible 
plug is not covered with scale. Externally look out for leaks 
on tube ends and around the girth seam and blow-off pipe. 
Also look out for blisters and bagging. Examine brick-work. 
It is not good practice to open tube doors till boiler has 
cooled off a little. 



INSPIRATORS. 

What is an inspirator? 

An inspirator is used to feed water in a boiler. It is an 
auxiliary to a pump in case it fails. 

Where is the steam taken from? 

The steam is taken from the highest part of the boiler. 

How do you start an inspirator? 

To start an inspirator, all valves except the force valve and 
main steam valves should be open. First open steam valve 
until water flows out of overflow, then shut middle valve and 
open the force valve a quarter-way, then close overflow. 

Where does the inspirator get its power? 

The steam escapes from the boiler with great velocity, and, 
as it passes through the suction jet, draws the air along with 
it, and thus creates a vacuum. Atmospheric pressure forces 
the water up into the suction pipe across an open space, and 
through the force jet, the steam and water mingling, and the 
steam is condensed; giving up its great velocity to the water,, 



42 PRACTICAL STATIONARY ENGINEERING 




Inspirators. 



BOILERS 43 

is penetrated into the boiler against a higher pressure than 
itself. 

The inspirator connection should be taken from a separate 
pipe from the steam-space, not from the steam pipe to engine. 
Inspirators will pump against one-half as much more pressure 
as is on boiler. A common inspirator will not pump at less 
than 20 pounds' pressure. 

What is the difference between an inspirator and injector? 

The inspirator and injector are practically the same. In- 
jectors may be handled with one lever. 



WATER PER HORSE POWER. 

Average amount of water required per horse power per 
hour for triple expansion engines, about 14 pounds; compound 
engines, 18 pounds; simple condensing engines, 23 pounds; 
single automatic cut-off, 30 pounds; high speed, 35 pounds; 
and throttling side- valve engine, 45 pounds. Grate designed 
to burn 12 pounds of coal per hour for each square foot of 
grate area. 

Water-heating surface for bituminous coal in horizontal 
tubular boilers should be from forty to forty-four times the 
area of the grate, and thirty-five times grate area for hard 
coal. In upright boilers the steam-heating surface should 
be included to obtain total heating surface. 

To find amount water boilers must evaporate, multiply 
pounds of water used by engine, as given above for each horse 
power per hour, and by the horse power required. 

To find the heating surface of the shell, multiply one-half 
of the circumference of boiler, in feet, by length of shell, in 
feet, exposed to fire. 



44 PRACTICAL STATIONARY ENGINEERING 

To find the heating surface of tubes, multiply inside area 
in square feet of 1 foot in length of tube by the length of 
tube and by the number of tubes. Adding to this the ex- 
posed surface of shell and back head will give total heating 
surface. 

To find the proper area of chimney, multiply collective 
area of tubes by 9, and divide by square root of height of 
chimney. 

To find the proper height of chimney, multiply collective 
area of tubes by 9, and divide product by area of chimney, 
and square the quotient. 



HEAT. 

To find units of heat required to raise temperature cor- 
responding to one gauge pressure to that of another. 

Rule. — Find the square root of the gauge pressures, sub- 
tract these values, and multiply remainder by 14J. 

Example. — Find the number of heat units required to raise 
the pressure from 81 pounds' gauge pressure to 144 pounds' 
gauge pressure. 

V~8T= 9 12 141 = 14.3 
A/l44 = 12 9 .3 

3 42.9, say 43 heat units required. 

To find units of heat required to raise temperature of 1 
pound of water from 32° F. to temperature due to pressure. 

Rule. — Extract square root of gauge pressure, and multiply 
this by 14J. To this product add 164. 



BOILERS 45 

Example. — Find the number of heat units required to raise 
water from 32° F. to 180 pounds gauge pressure. 

Vl80(13.41 14.33 = 14* 



1 


13.41 


23)~80~ 


1433 


69 


5732 


264) 1100 


4297 


1056 


1433 


2681) 4400 


192.1453 


2681 


164 




356.14 = number of heat units 




necessary. 


Rule. — To find the 


temperature of steam, find square 


root of gauge pressure, and multiply this value by 14. 


To this product add ] 


L99. 


Example. — What is 


the temperature of steam when the 


gauge registers 144 pounds' pressure? 


^144 = 12 


12 




14 




~48 




12 




~168 




199 




367° F. 



What is meant by latent heat? 

It is the amount of heat necessary to change liquids to gas, 
or solids to liquids, without increasing the temperature. 

What would be an illustration of latent heat? 

The melting of ice at 32° F. and the boiling of water at 
212° F. 



46 PRACTICAL STATIONARY ENGINEERING 

Rule.— To find the latent heat of steam, subtract ten 
times the square root of the gauge pressure from 977. 

Example. — Find the latent heat at 144 pounds' gauge 
pressure. 

Vl44~=i2 977 

10 120 

. 120 857° latent heat. 



CHAPTER II. 
SAFETY-VALVE. 

Why are safety-valves placed on boilers? 

To provide for the release of steam in case it should rise 
above the pressure representing the safe-working pressure of 
boiler. 

What are the kinds or types of valves? 

Lever, pop, or spring, and dead-weight valves. 

What are the most common? 

Lever and pop valves. 

Describe a lever valve. 

The lever valve consists of a valve proper, with stem 
guided in such a manner as to keep it from becoming jammed 
while lifted from seat. This stem is fastened usually b}^ a 
pin to the lever. On one end of this lever is hung a weight, 
and the other pivoted to a bonnet or yoke on top of valve. 
This pivotal point is called the fulcrum. 

Describe a pop, or spring, valve. 

The pop-valve is constructed practically the same with 
the exception that a spring is substituted for the lever and 
ball, and valve is set to the required pressure by means of a 
screw at top by which the spring is compressed to the desired 
pressure at which the boiler is to blow off. 

Where should a safety-valve be set in relation to the 
boiler? 

It should be placed where there is no possible chance of 
cutting off communication with the boiler; that is, there 
should be no other valve between it and boiler. Usually, 



48 



PRACTICAL STATIONARY ENGINEERING 



it is placed on a flange especially provided for it directly 
on top of the boiler. 

If valve should stick and pressure run up higher than in- 
tended to blow off, what would you do? 

Close ash-pit doors, bank fires, turn steam on building 
slowly, or any other means to use up steam formed, but under 




■Hi 

Figure 10 



Figure 11. 



no condition raise the safety-valve before steam had dropped 
to pressure intended to blow off. 

Can a safety-valve be too large? 

Yes, if too large, the velocity of steam through the valve 
may carry along with it the water in the boiler, thereby 
lifting the water from the sheet. Valves should be made 



SAFETY-VALVE 



49 



large enough to carry off all the steam the boiler is able to 
make. 

How do you determine the size of valve? 

The area of valve in square inches is equal to the square 
feet of grate surface divided by 3. 

In calculating for weight of ball, length of arm, and 




Figure 12. 



pressure at which a valve will blow, what data must be 
obtained from the valve? 

Area of valve, weight of lever, distance from fulcrum to 
centre of gravity of lever, weight of valve and stem, and dis- 
tance from fulcrum to centre of valve stem. 



50 PRACTICAL STATIONARY ENGINEERING 

How do you determine the centre of gravity of the lever? 

Detach the lever from the valve, and move it along a knife 
edge until it is in balance, measure the distance "A " from ful- 
crum to this point, weigh the lever accurately. 

The reason for this being that the weight of lever at its centre 
of gravity, multiplied by the distance from the fulcrum "A" 
and divided by the distance from fulcrum to centre of valve 
stem U B, V is the pressure exerted on the stem of the valve 
by the weight of lever. Our calculations would not be correct 
if this value were not taken into consideration, as will be 
shown by study of the following examples. 

To find the pressure at which a safety-valve will blow 
off. 

Rule. — Multiply the weight of ball in pounds by the length 
of lever in inches, and divide the product by the distance 
in inches from fulcrum to centre of valve stem (call this 
quotient U A"). 

Multiply weight of lever in pounds by the distance in 
inches from the fulcrum to centre of gravity of lever, and 
divide the product by the distance in inches from fulcrum to 
centre of the valve stem (call this quotient U B"). 

Add these above values " A" and a B" to the weight of 
valve and stem, and divide this sum by the area of the valve 
in square inches. 

Example. — At what pressure will a valve release the steam 
if the ball weighs 60 pounds, weight of lever 30 pounds, weight 
of valve and stem 8 pounds, length of lever 34 inches, dis- 
tance from fulcrum to centre of gravity of lever 16 inches, 
distance from valve centre to fulcrum 6 inches, diameter of 
valve 3 inches? 



SAFETY-VALVE 51 

60 = weight of ball. 
34 = length of lever. 



240 

distance from ful- 180 



crum to centre valve = 6)2040(340 lbs. = the effect of the 
18 ball at the valve stem. 

24 
24 



30 = weight of lever. 
16 = fulcrum to centre gravity 
~180 of lever. 

( distance from ful- 30 

I crum to centre valve = 6)480(80 lbs. = effect of weight of 
48 lever at valve stem. 

340 = lbs. clue to ball. 
80 = lbs. due to lever. 
8 = lbs. weight of valve and stem. 
428 = total pressure downward at valve stem. 

3-inch diameter valve, 3x3 = 9 .7854 

9 



7.0686, say 7.07 square inches. 

area of valve = 7.07)428. 00(60. 53 lbs. = pressure at. which 
4242 valve will blow off. 




52 PRACTICAL STATIONARY ENGINEERING 

To find distance from fulcrum to centre of ball. 

Rule. — Multiply the area of valve in square inches by the 
blow-off pressure, and from this product subtract the weight 
of valve and stem (call this value "A"). 

Multiply the weight of lever in pounds by the distance in 
inches from the fulcrum to centre of gravity, and divide this 
product by the distance from fulcrum to centre of valve stem 
(call this value "B"). 

Subtract "B" from "A," and multiply the remainder by 
the distance from fulcrum to valve stem. Divide this last 
result by the weight of ball. 

Example. — In the preceding example suppose we wish to 
have the valve blow off at 55 pounds, how far from ful- 
crum must weight be placed? 

7.07 = area of valve. 

55 = pressure to blow off at. 
3535 
3535 



388.85 = pressure on valve. 

8.00 = weight of valve and stem. 
380.85 = pressure on valve. 



30 = lbs . weight lever. 
16 = distance from fulcrum to ) 
IgO centre of gravity. ) 

distance from ful- 30 
crum to centre valve = 6)480 (80 = lbs. effect at valve of 
48 stem of weight of lever. 



SAFETY-VALVE 53 



380.85 = pressure on valve. 
80.00 = effect of valve. 



300.85 = weight for ball to balance. 

6 = distance from fulcrum to valve stem. 



1805.10 



weight of ball = 60)1805.10(30.08=inches from fulcrum. 
180 
510" 
480 



To find the weight of ball. 

Rule. — Multiply the area of valve in square inches by the 
blow-off pressure, and subtract the weight of valve and stem 
from the product (call this value "A"). 

Multiply the weight of lever in pounds by the distance in 
inches from fulcrum to centre of gravity, and divide this 
product by the distance in inches from fulcrum to centre of 
valve stem (call this value U B"). 

Subtract U B" from "A," and multiply the remainder by 
the distance in inches from the fulcrum to centre of valve 
stem. Divide this product by distance from fulcrum to centre 
of weight. 

In the preceding example what must the ball weigh to 
blow off at 75 pounds? 

area of valve = 7.07 = square inches. 
75 = pressure. 

3535 
4949 



530.25 = pressure on valve. 

8.00 = weight of valve and stem. 
522.25 = actual pressure on valve. 



54 PRACTICAL STATIONARY ENGINEERING 

30 = weight of lever. 
16 = distance from fulcrum to 
180 centre of gravity. 

{ distance from ful- 30 

(crum to valve stem = 6)480(80= lbs. due to weight of lever. 
48 

522.25 = actual pressure. 
80.00 = due to lever weight. 



442.25 [valve stem, 

(distance from ful- 6 = distance from fulcrum to 

\ crum to weight = 34)2653.50(78.04 = lbs. weight of ball. 
238 

273 

272 



150 
136 



TUBES. 

What proportion is used for the relation of collective tube 
area to grate area? 

It is usually made one-eighth the area of grate. 

How are the tubes measured? 

By the outside diameter. 

How are pipes measured? 

By the inside diameter. 

What size tubes are usually placed in boilers up to 48 inches 
diameter? 

Common practice is to use tubes 2\ inches diameter. 



SAFETY-VALVE 55 

What size tubes are used between 48 inches and 60 inches 
diameter? 

Usually 3 inches diameter, and above 60 inches use 3J- 
inch tubes. 
What is the average thickness of tubes? 
Usually from 0.10 inch to 0.17 inch thick. 
What thickness is commonly used for stay- tubes? 
Stay-tubes are usually J inch thick. 

Example. — What is the heating surface per foot for a 3-inch 
tube I inch thick? 

3 inches = diameter of tube. 
I inch = 2 X i, or twice thickness. 
2f inches = inside diameter =2.75 inches. 

3.1416 = constant. 
2.75 = inside diameter. 



157080 
219912 
62832 



8. 639400 = inside circumference. 
12 = inches per foot. 



172788 
86394 



103.6728 = number of square inches. 



56 PRACTICAL STATIONARY ENGINEERING 

( square inches 

(per square foot = 144) 103.6728(.7199 square feet area per 
1008 foot length, say .72 

287 
144 



1432 
1296 
1368 
1296 



How do you find the total tube-heating surface of boiler? 

Rule. — Multiply heating surface per foot of length by the 
length of tubes in feet, and that product by the number of 
tubes in boiler. 

Example. — A boiler having 110 3-inch tubes, J inch thick, 
is 12 feet between front and back heads. What is the tube- 
heating surface? 

From preceding example, heating surface per foot length = 

.72 = square feet. 
12 = length of tubes in feet. 



144 

72 

8.64 = square feet per tube. 
110 = number of tubes. 



864 
864 



950.40 = square feet total heating surface. 



SAFETY-VALVE 57 

Example. — In the preceding example what is collective 
area in square feet of tube openings? 
3-inch diameter tube. 
i = thickness = J X 2 = J. 
2f = inside diameter. 

2.75 
2.75 
1375 
1925 
550 



7.5625 
.7854 = constant. 



302500 
378125 
605000 
529375 
5.93958750 = area in square inches. 

^ square inches 

( in one foot = 144)5.93958(.0412 = area in square feet. 
576 

179 

144 



355 

288 



.0412 = area of tubes, square feet. 
110 = number of tubes. 



412 
412 



4.5320 = collective area of in square feet. 



58 PRACTICAL STATIONARY ENGINEERING 

Example. — What percentage of the total boiler volume do 
the tubes represent in the preceding example, if the diam- 
eter is 60 inches? 

60 inches = diameter shell. 

60 
3600 
.7854 = constant. 



14400 
18000 
28800 
25200 
2827.4400 = area in square inches. 

$ square inches 

^per square foot = 144) 2827.44 (19. 635 = area square feet. 
144 







1387 






1296 






914 






864 






504 






432 






720 






720 


19.64 = 


= area. 




12 = 


= length in 


feet. 


3928 






1964 







235.68= cubic feet volume of shell, say 235.7 



SAFETY-VALVE 59 



3 inches = diameter tube. 
3 
"9 

.7854 
9 



7.0686 = area in square inches, 
square inches per square foot= 144) 7. 0686(. 049 = square 

576 feet area. 

1308 
1296 
.049 = area square feet. 

l=foot. 
.049 = cubic feet for 1 foot length of tube. 

12 = length of shell or tube. 
~98 
49 



588 
110= number of tubes. 



588 
588 



64.680= cubic feet occupied by tubes, say 64.7 

( percentage of tubes volume 

I to shell volume = 235.7)64.700(.27=percent.shellvolume. 
4714 



17560 
16499 



60 PRACTICAL STATIONARY ENGINEERING 



BOILER PLATES* 

What thickness plate should be used on a 40-inch boiler to 
carry 125 pounds' pressure, tensile strength of plate 60,000 
pounds? 

125 = steam pressure. 

6 = factor of safety. 
750 

20 = h diameter boiler. 



15000 



tensile strength of plate = 60,000) 15000. 0(.25, or J-inch thick- 

120000 ness of plate. 

300000 
300000 



BURSTING PRESSURE. 

How do you determine the bursting pressure of a boiler with 
single-riveted joint? 

Rule. — Multiply the tensile strength of plate in pounds 
per square inch by the thickness of the weakest plate in 
hundredths of an inch. Multiply this product- by the per- 
centage of strength of a single- riveted joint. Divide the 
quotient by one-half of the diameter of boiler. This will 
give the bursting pressure. Divide the last product by 5, 
which is the factor of safety. This will give safe-working 
pressure to carry. 

Example. — What is the bursting pressure of a boiler, 
single riveted, having ^-inch steel plates, 60,000 pounds' 



SAFETY-VALVE 61 

tensile strength of plates, assuming strength of joint to be 56 
per cent., diameter of boiler 40 inches, factor of safety 5? 

60,000 = tensile strength of plate. 
.25 = thickness of plate. 



300000 




120000 




15000.00 




.56 


= per cent, of strength of joint 


90000 




75000 




8400.00 




i diameter boiler = 40 


-4- 2 = 20)8400.00(420 = lbs. bursting 




80 pressure. 




"40 




40 



factor of safety = 5)420(84= lbs. safe-working pressure. 
40 
~20 
20 

To determine bursting pressure of double- riveted joint. 

Rule. — Multiply the tensile strength of plate in pounds per 
square inch by the thickness of the weakest plate in hun- 
dredths of an inch. Multiply this product by the percentage 
of strength of a double-riveted joint. Divide the quotient 
by one-half diameter of the boiler. This will give the burst- 
ing pressure. Divide the last product by 5, which is the 
factor of safety. This will give the safe-working pressure. 

Example. — What is the bursting pressure of a boiler 
double riveted, having |-inch steel plate, tensile strength 



62 PRACTICAL STATIONARY ENGINEERING 

of plate 60,000 pounds, assuming strength of joint to be 70 
per cent., diameter of boiler 40 inches, and factor of 
safety 5? 

60,000 = tensile strength of plate. 
.25 = thickness of plate. 



300000 
120000 



15000.00 

.70 = per cent, of strength of joint. 



10500.00 



i diameter boiler =40-s-2 = 20) 10500. 00(525= lbs. bursting 

100 pressure. 

~50 
40 

"Too 

100 

factor safety =5) 525(105= lbs. safe-working pressure. 
5 

~25 
25 

How do you find bursting pressure of triple- riveted joint? 

Rule. — Multiply the tensile strength of plate in pounds per 
square inch by the thickness of the weakest plate in hun- 
dredths of an inch. Multiply this product by .75, which is 
the percentage of strength of a triple-riveted joint. Divide 
the quotient by one-half the diameter of boiler. This will 
give the bursting pressure. Divide the last product by 5, 



SAFETY-VALVE 63 

which is the factor of safety. This will give the safe-work- 
ing pressure to carry. 

Example. — What is the bursting pressure of a boiler 
triple riveted, having f-inch steel plate, tensile strength 
60,000 pounds, assuming strength of joint to be 75 per 
cent., diameter of boiler 66 inches, factor of safety 5? 

60,000 = tensile strength of plate. 
.375 = thickness of plate. 



300000 
420000 
180000 




• 




22500.000 

.75 = per cent. 
112500 
157500 


strength of joint. 




16875.00 








diameter of boiler =66 -*■ 2 


= 33)16875.00(511.36 = 
165 bursting 
37 
33 


=lbs. 

pressure, 




~l5 
33 
~120 

99 








210 







64 PRACTICAL STATIONARY ENGINEERING 

factor safety = 5)511.36(102.2 = lbs. safe working pressure, 
5 
"TT 
10 
~13 
10 
~36~ 
To find the bursting pressure of a butt-strap, triple-riveted 
joint. 

Rule. — Multiply the tensile strength of plate in pounds 
per square inch by the thickness of the weakest plate in hun- 
dredths of an inch. Multiply this product by "."82, which is 
the percentage of strength of a butt-strap joint. Divide the 
quotient by one-half the diameter of boiler. This will give the 
bursting pressure. Divide the last product by 5, which is the 
factor of safety. This will give the safe- working pressure to 
carry. 

Example. — What is the bursting pressure of a boiler with 
butt-strap joints, triple riveted, having f-inch steel plates, 
tensile strength 60,000 pounds, assuming strength of joint 
to be 82 per cent., diameter of boiler 66 inches, factor of 
safety 5? 

60,000 = tensile strength of plate. 

.375 = thickness of plate. 
300000 
420000 
180000 



22500.000 

.82 = per cent, strength of joint. 



45000 
180000 
18450.00 



SAFETY-VALVE 65 

18450.00(559 =lbs. bursting 
165 pressure. 



| diameter boiler=66 -*- 2 = 33) 18450.00(559= lbs. bursting 



195 
165 



300 
297 



factor of safety = 5)559(111.8=lbs. safe-working pressure. 
5 

5 

T 

5 
~40~ 




Figure 13. 



66 PRACTICAL STATIONARY ENGINEERING 



AREA OF BOILER HEAD TO BE BRACED. 

How would you ascertain the number of braces which are 
necessary to strengthen that part of the boiler head which 
is not stayed by the tubes ? 

It is first necessary to know its area. The part to be stayed 
is a segment of a circle. The length of the segment is meas- 
ured 2 inches above the tubes, and the height or width 
should be measured from a line, drawn 2 inches above the 
tubes, to a point within 3 inches from the top of the boiler 
shell, as shown in the illustration by the clotted line. Some 
allow a margin of 2 inches. 

Rule. — Deduct from diameter of shell 4 inches, and find 
area of this inner circle. Subtract from one-half this area 
the number of square inches in the rectangle (shown in the 
cut). Multiply this remainder by the steam pressure in 
pounds per square inch. Divide this remainder by the 
allowable pressure on each stay (which is found by multi- 
plying area of stay by 5,000), the value usually taken in 
designing. The quotient will be the number of stays neces- 
sary to support the segment. 

Example. — How many lj-inch stays should be used on a 
boiler 60 inches in diameter, carrying 100 pounds' boiler 
pressure, allowing 5,000 pounds per square inch of area on 
stay? 



SAFETY-VALVE 



67 



2 inches supported all around, to be deducted from diameter. 
2 



60 

4 

~56 = 

56 

336 

280 



inches new diameter. 



2)2463(1231.5 = 1 area ring. 



3136 




56 = length rectangle. 


.7854= 


= constant. 


7 = height rectangle. 


12544 




392 = area rectangle. 


15680 






25088 




1231.5 


21952 


= area inside ring. 


392.0 


2463.0144 


839. 5 = square inches, 






area segment to be braced. 




839.5 =area. 






100 = steam pressure. 




83950.0 = pressure per square inch on segment. 


14 = 


1.5 = diameter stay. 
1.5 





75 
15 



2.25 

.7854 



900 
1125 
1800 
1575 



5000 = allowable pressure. 
1.76 = area of stay in 
square inches. 



30000 
35000 
5000 



[each stay. 
8800.00 = allowable pressure on 



1.767150 = area stay. 



68 PRACTICAL STATIONARY ENGINEERING 

8800)83950(9.53 = number stays necessary, make 10, 
79200 lj-inch stays. 

47500 
44000 



35000 
26400 



How do you determine strain on longitudinal seam ? 

Rule. — To determine the strain produced on longitudinal 
seams tending to tear the seam asunder, multiply the given 
pressure per square inch in pounds by one-half of the diameter 
of the boiler in inches, and the product will give the strain, 
in pounds, on each longitudinal inch along the shell of the 
entire boiler as well as on the longitudinal seam. 

Example. — What is the strain in pounds per inch length on 
the longitudinal seam of a boiler working under 150 pounds' 
steam pressure, diameter 48 inches ? 

150 = steam pressure. 
24 = \ diameter boiler. 
600 
300 



3600= lbs. strain per inch on seam. 

How do you determine the strain per inch on girth seam? 

Rule. — Multiply area of boiler head in square inches by the 
steam pressure, and divide by the circumference of boiler. 

Example. — What is the strain per inch on the girth seam 
on the boiler in above example ? 





SAFETY-VALVE 


area =48 






48 


circum 


ference = 3.1416 


384 


48 


192 




251328 


2304 




125664 


.7854 




150.7968, say 150.8 


9216 






11520 




150.8)271434.0(179.99 


18432 




1508 


16128 




12063 


1809.5616 




10556 
15074 


18 


tf)9.56 = 
150 = 


= area boiler head. 13572 




steam pressure. 15020 


£ 


)047800 
$956 


13572 


tt 


14480 


271434.00 


13572 



say 180 lbs. strain on girth seam. 



The strength of the shell of a cylindrical boiler to resist 
a pressure within it is inversely proportional to its diameter 
'and directly proportional to the thickness of the plate of 
which it is formed. For instance, take three cylindrical 
boilers, each made of J-inch plate, the first one 2 feet 6 inches 
in diameter, the second twice that, or 5 feet in diameter, 
and the third twice that, or 10 feet in diameter; and if the 
2-feet-6-inches boiler is safe for a working pressure of 180 
pounds to the square inch, then the 5-foot boiler will be safe 
for exactly one-half that amount, or 90 pounds per square 
inch, and the 10-foot boiler will be safe for half the working 
pressure of the 5-foot boiler, which would be 45 pounds. 



70 PRACTICAL STATIONARY ENGINEERING 

The working steam pressure allowable on boilers con- 
structed of plates inspected as required when single riveted 
shall not produce a strain to exceed one-fifth of the tensile 
strength of the steel plate of which such boilers are con- 
structed. 

How would you find the required diameter of a boiler? 

To determine the required diameter of a boiler, with single- 
riveted longitudinal seam, when the working pressure, thick- 
ness, and tensile strength are given. 

Rule. — Divide the product of the tensile strength of plate 
times the thickness of the plate by the steam pressure times 
6. Multiply this quotient by 2, the product will be the 
diameter of boiler required. 

Example. — What should the diameter of boiler be having 
-J~inch steel plate, 60,000 pounds' tensile strength, 125 pounds' 
steam pressure? 

60, 000 = tensile strength of plate. 
.25 = thickness of plate. 



300000 




120000 




15000.00 






125 = steam pressure. 




6 = constant. 




750 




750)15000(20 




1500 



20 X 2 = 40 = diameter boiler. 

How do you determine the thickness of plate for a boiler 
with single-riveted longitudinal seams, when the diameter, 
tensile strength of material, and working pressure are given? 



SAFETY-VALVE 71 

Rule. — Multiply the steam pressure in pounds per square 
inch by 6 and by one-half diameter of boiler. Divide this 
product by the tensile strength of the plate. The quotient 
will be the thickness of plate in decimals of an inch. 

What thickness of plate should be used on a boiler 40 
inches diameter, 125 pounds' working pressure, assuming 
tensile strength of plate to be 60,000 pounds? 

125 = working pressure. 
6 = constant. 



= \ diameter boiler. 



( tensile strength 

t of plate=60 ; 000)15000.00(.25 = i-mch thickness of plate. 
120000 

300000 

300000 



CHAPTER III. 
RIVETED JOINTS- 

Define a single- riveted lap joint. 

In a single- riveted lap joint the surfaces of the plate overlap 
and the plates are held in position by one row of rivets. 

Define a double- riveted lap joint. 

In a double- riveted lap joint the surfaces of the plates 
overlap and the plates are held in position by two rows of 
rivets. 

Define a butt-strap joint. 

A joint in which the edges of the plate come together 
having a true circle, and are held in position by riveting 
through the inside and outside cover plate. 

Define a double- riveted butt joint. 

It is a joint in which the edges of the plate come together 
forming a true circle with inner and outer cover plates and 
having an inner row of rivets in double shear and outer row 
in single shear. 

Define a triple- riveted butt joint. 

A joint in which the edges of the plates come together 
forming a true circle and having inner and outer cover plates 
with the inner rows of rivets in double shear and the outer 
row in single shear. 

In what way may a riveted joint fail? 

1st, by shearing rivets. 

2d, by tearing plates between the rivets. 

3d, by crushing the rivet or plate in front of a rivet or by 
a combination of two or more of the above causes. 



RIVETED JOINTS 



73 



3 
3 



Da 




rf> 




<-> 




74 PRACTICAL STATIONARY ENGINEERING 

Figure 14 shows in what way a riveted joint may fail. 

At A is shown the shearing of a rivet. 

At B is shown tearing plate between rivet holes. 

At C is shown crushing plate in front of rivet. 

How is the resistance to shear one rivet found? 

By multiplying area of rivet by its shearing strength. 

How is the resistance to tear the plate between the rivets 
found? 

Multiply the distance between rim edges of hole by the 
thickness of plate and this product by the given tensile 
strength of the plate. 

How is the resistance to crush the rivet or plate found? 

Multiply diameter of rivet by the thickness of plate and 
the product by the crushing strength of the rivet or plate. 

How is the strength of solid plate found ; and why used? 

By multiplying the pitch of rivets by the thickness of plate 
and this product by the tensile strength given for the plate. 
It is used for calculating the efficiency of the joint 

What is meant by a single shear of a rivet? 

Single shear of a rivet is where it passes through two 
plates and would shear or cut-off in one plane only. 

Give an illustration of a rivet in single shear. 

Rivets are in single shear in a single- riveted lap joint. 

What is meant by double shear? 

Double shear of a rivet is where the rivet passes through 
three plates and it is possible to shear rivet in two planes. 

Give illustration of a rivet in double shear. 

The rivets in a double- riveted or triple-riveted butt joint. 

What is meant by the tensile strength of a plate? 

The tensile strength of a plate is the number of pounds the 
plate will stand in tension or pulling apart for each square 
inch of its area. 



RIVETED JOINTS 75 

What is meant by the shearing strength of a plate? 

The shearing strength of a plate is the number of pounds 
necessary to cut across the plate. 

What is meant by the crushing strength of a plate? 

The crushing strength of a plate is the number of pounds 
necessary to crush or press together the surfaces of the plate. 

What is the average tensile, shearing, and crushing 
strength of steel and wrought-iron plate? 

Steel. Iron. 

Tensile 60,000 pounds 45,000 pounds 

Shearing 50,000 " 38,000 " 

Crushing 90,000 " 74,250 " 

What is a test piece? 

A piece cut from the sheet from which tests are made to 
ascertain the various strengths of the plate to be used. 

How is the pitch of rivets for single- riveted joints found? 

Rule. — Multiply the diameter of rivet hole by 7. Divide 
this product by eight times the thickness of the plate, and 
to this quotient add 1, then multiply this sum by diameter 
of rivet hole. 



76 PRACTICAL STATIONARY ENGINEERING 

Example. — What pitch should be used for a single- riveted 
joint having f-inch rivet and J-inch plate? ' 

Diameter of rivet hole, f=.75 

7 = constant. 
5.25 
thickness of plate, \ = .25 

constant = 8 

2^00)5.25(2.62 
400 



1250 
1200 



500 
400 

2.62 

1.00 to be added. 



3.62 

.75 = diameter of rivet hole. 



1810 
2534 



2.7150 = pitch, say 2| inchea 



RIVETED JOINTS 77 

How is the pitch of rivets for a double- riveted lap joint 
found? 

Rule. — Multiply diameter of rivet hole by 7. Divide this 
product by four times the thickness of plate, to this quotient 
add 1, then multiply this sum by diameter of rivet hole. 

Example. — What pitch should be used for a double-riveted 
lap joint having f-inch rivets and f-inch plate? 



rivet diameter, J =.75 




7 = constant. 




f-inch plate =.375 5.25 1 


.50)5.25(3.5 


constant = 4 


450 


1.500 


750 




750 


3.5 




1.0 = to be added. 




T5 




.75 = diameter rivet hole. 




225 




315 





3.375 = pitch of rivets 3| inches. 

How is the pitch of rivets for a double- riveted butt joint 
found? 

Rule. — Multiply diameter of rivet hole by 7. Divide this 
product by two times the thickness of plate, to this quotient 
add 1, then multiply this sum by the diameter of rivet hole. 



78 PRACTICAL STATIONARY ENGINEERING 

Example. — What pitch should be used for a double-riveted 
butt joint having ^-inch rivets and T Vinch plate? 

diameter of rivet hole, H = .6875 

7 = constant. 
4.8125 

thickness of plate, T 9 ^ = .5625 

2 = constant. 
1.1250 

1.125)4.8125(4.27 
4500 



3125 
2250 

8750 

7875 



4.27 875 

1 to be added. 
5^27 

.6875 = diameter of rivet hole. 
5.27 = sum. 



48125 
13750 
34375 



3.623125 = pitch of rivet 3f inches. 

How is the diameter of a rivet hole found for a single-riveted 
and double- riveted lap joint? 

Diameter equals thickness of plate plus | of an inch. 

How is the diameter of a rivet hole found for butt joints 
with cover plates? 

Diameter equals one and one-quarter times the thickness 
of plate. 



RIVETED JOINTS 



79 






3^ 

53 IS 




C>-^- 




80 PRACTICAL STATIONARY ENGINEERING 

How much smaller is the diameter of a rivet than the 
rivet hole? 

Usually the rivet is T Vinch smaller in diameter than the 
hole, to allow rivet to upset and completely fill hole when 
driven and headed. 

What is staggered riveting? 

Joints having two rows of rivets, the rivets in the second 
row being placed midway between rivets of first row. 

What is chain riveting? 

Joints having two rows of rivets, with the second row in 
line with or above rivets in first row. 

What is meant by the efficiency of a joint? 

The relation of strength of the joint to the strength of the 
solid plate. 

How is the efficiency of a joint found? 

Rule. — 1st, multiply pitch of rivets by strength of plate, 
and this product by thickness of plate. 

2d, subtract diameter rivet hole from the pitch of rivets, 
multiply this remainder by the thickness of the plate and the 
tensile strength of plate. 

3d, multiply area of one rivet by the number of rivets, 
and multiply this product by the shearing strength of rivet. 

4th, divide the weaker of these by the strength of solid 
plate, the quotient will be the percentage of strength of the 
joint? 

What values may safely be taken for the efficiency of riveted 
joints? 

Single -riveted joints, 56%. 
Double- " " 70" 

Triple- " " 75 " 

Butt-strap " " 85 " 



RIVETED JOINTS 



81 




Figure 17. 



82 PRACTICAL STATIONARY ENGINEERING 

SINGLE-RIVETED LAP JOINT. 

P represents pitch of rivet. (See rule.) 

A represents lap of plate, and usually made to equal 
three times the diameter of rivet. 

B represents distance between holes. 

C, lap from centre of rivet and usually equal to one and 
one-half times the diameter of rivet. 

Find the efficiency of a single-riveted lap joint by rules 
previously given. 

Example. — Using f-inch iron rivet, J-inch steel plate, and 
lf-inch pitch, assume tensile strength of plate to be 60,000 
pounds, shearing strength of rivet 38,000 pounds. 

60,000 

.25 = 1 inch =.25 
300000 
120000 



15000.00 

1.75 = pitch=lf inches. 



7500000 
10500000 
1500000 



26250.0000=lbs. to break solid plate. 

15000 

1 = distance between holes. 



15000 = lbs. to break plate between holes. 



area f-inch rivet =.44 square inches. (See table.) 





RIVETED JOINTS 


38,000 




.44 




152000 




152000 




16720.00 = 


=lbs. to shear rivet. 



83 



26,250)15000.00(.5714 = 57.14 per cent, strength of 
131250 joint. 

187500 
183750 



37500 
26250 . 
112500 
105000 



DOUBLE-RIVETED LAP JOINT, 

P represents pitch of rivets. (See rule.) 

A represents lap of plate, and usually made to equal four 
and one-half times the diameter of rivet. 

B represents distance between holes. 

C, distance between rows of rivets, and usually equal to 
one and one-half times diameter of rivets. 

Example. — What is the efficiency of a double-riveted lap 
joint using f-inch iron rivet, ^-inch steel plate, 3-inch pitch, 
assuming tensile strength of plate 60,000 pounds, shear- 
ing strength of rivet 38,000 pounds? 



84 PRACTICAL STATIONARY ENGINEERING 




r^ n^ 



U7\_7 



^- 




Figure 18. 



RIVETED JOINTS 85 

60,000 

.25= J-inch thickness of plate. 



300000 
120000 



15000.00 

3 = pitch of rivet. 



45000 =lbs. to break solid plate. 

15000 
2.25= distance between holes. 



75000 
30000 
30000 



33750.00= lbs. to break plate. 

area f-inch rivet =.44 square inches. 
38,000 
.44 



152000 
152000 



16720. 00 = lbs. to shear 1 rivet. 
2 



33440 =lbs. to shear 2 rivets. 

45,000)33440.0(74.31= per cent, strength of joint. 
315000 
194000 
180000 



140000 
135000 



50000 



PRACTICAL STATIONARY ENGINEERING 




A 



(Jm/4. 



^ ^\wmm, 



a 



^^ 



qr qj qj 



B 



kf 



Figure 19, 



EIVETED JOINTS 87 

DOUBLE-RIVETED BUTT JOINT. 

P represents pitch of inner row. (See rule.) 

A represents width of outside cover plate. 

B represents distance between holes on outer row. 

C represents distance from first row to outer row. 

D represents width of inner cover plate. 

H represents distance from butt to first row of rivets. 

represents pitch of outer row of rivets. 

Example. — What is the efficiency of a double-riveted butt 
joint having f-inch steel plate, f-inch iron rivet, 2^-inch 
pitch inner row, 5-inch pitch outer row, assuming tensile 
strength of plate to be 60,000 pounds, shearing strength of 
rivets 38,000 pounds? 

1st, resistance to tear at outer row. 

5 inches — f =4J inches =4.25 = decimal. 

.375 = thickness of plate, 
distance between rivets =4.25 
1875 
750 
1500 



1.59375 

1.59 

60,000 
95400= lbs. to tear at outer 
plate. 

2d, resistance to shear. 

2 rivets in double shear and 1 rivet in single equals 5 
rivets in single shear. 



PRACTICAL STATIONARY ENGINEERING 

38,000= shearing strength of rivet. 
5 



190000 

.44 = area of rivet. 



760000 
760000 



83600.00 =lbs. to shear 5 rivets. 

3d, resistance to crush in front of 3 rivets. 

.375 = thickness of plate. 
3 = number of rivets. 



1.125 

.75 = diameter of rivet. 
5625 

7875 



.84375 

90,000 = crushing strength of plate. 

.84 



360000 
720000 



75600.00 =lbs. to crush in front of 3 rivets. 

4th, resistance to crush in front of 2 rivets and shear 1 
rivet. 

.375 = thickness of plate. 
2 = number of rivets. 
750 
.75 = diameter of rivet. 



3750 
5250 
.56250 



RIVETED JOINTS 



38,000 = shearing strength of rivet. 
.44 = area of rivet. 



152000 
152000 



16720.00 
90,000 = lbs. crushing strength of plate. 
.56 



540000 
450000 
50400.00 
16720 



67120.00 =lbs. to crush in front of 2 rivets and 
shear 1 rivet. 

Values from calculations then equal: — 

95,400 pounds to tear at outer row. 

83,600 pounds to shear 5 rivets. 

75,600 pounds to crush in front of 3 rivets. 

67,120 pounds to crush in front of 2 rivets and shear 1 rivet. 

Select lowest value, 67,120 pounds. 
Shearing strength of solid plate = 

.375 = thickness of plate. 
5 = outside pitch. 
L875 
60,000 = tensile strength of plate. 
1.875 



300000 
420000 
480000 
60000 
112500.000 =lbs. strength of solid plate. 



90 PRACTICAL STATIONARY ENGINEERING 

112,500)67120.0(.5967 = 59.67 per cent, strength of 
562500 joint. 

1087000 
1012500 



755000 
675000 
800000 
787500 



TRIPLE-RIVETED BUTT JOINT. 

P represents pitch of rivets, inner rows. 

A, width of outside cover plate. 

B, distance between holes, outer row. 

C, width of inside cover plate. 

D, pitch of outer row of rivets. 

Example. — What is the efficiency of a triple-riveted butt 
joint having T 7 ^-inch steel plate, J-inch iron rivets, pitch of 
inner rows 2f inches, pitch of outer row 5J inches, assum- 
ing tensile strength of plate to be 60,000 pounds and shear- 
ing strength of rivets to be 38,000 pounds, thickness of 
cover plates T \ inches? 

1st, resistance to tear at outer row. 

5i inches — J inch=4j inches = distance between holes. 

plate, T % = .4375 = decimal. 

60,000 = strength of plate. 
26250.0000 
4.25 = distance between holes. 



131250 

52500 
105000 
111562.50= lbs. to break plate between holes. 



RIVETED JOINTS 



91 






t+7 



W qx 



^2a 



ta 





to 








Figure 20. 



92 PRACTICAL STATIONARY ENGINEERING 

2d, resistance to shear rivets. 

4 rivets in double, 1 in single shear, equal 9 rivets in single 
shear. 

38,000 

.6 = area of rivet. 



22800.0 
9 



205200 =lbs. to shear 9 rivets. 
3d, resistance to crush in front of 5 rivets. 

Five times diameter of rivet times thickness of plate, by 
this product times the crushing strength of plate, plus di- 
ameter of rivet times thickness of inner cover plate, times 
crushing strength of plate. 



diameter of rivet, .875 = 


= decimal. 




. 5 = 


= number of rivets. 




4.375 






.4375 = 


= thickness of plate. 




21875 






30625 






13125 






17500 






1.9140625 




.875 = 


= diameter of rivet. 


.4375 = 


= thickness of cover plate. 


4375 






6125 






2625 






3500 






.3828125 





RIVETED JOINTS 93 

.38 
90,000= crushing strength of steel. 



34200.00 



1.914 

90,000= crushing strength of steel. 



172260.000 
34200 



206460 = crushing strength of plate in lbs. in 
front of 5 rivets. 

4th, resistance to crush in front of 4 rivets and shear 
1 rivet. 

Four times diameter of rivet multiplied by thickness of 
plate, times crushing strength of plate, plus area of rivet mul- 
tiplied by the shearing strength. 

,| diameter of rivet, .875 = decimal. 
4 



3.500 

.4375 = thickness of plate. 



17500 
24500 
10500 
14000 
1.5312500 



94 PRACTICAL STATIONARY ENGINEERING 

38,000 = shearing strength of rivet. 
.6 = area of one rivet. 



22800.0 



1.53 

90,000 = crushing strength of plate. 
137700.00 

22800 



160500= lbs. to crush in front of 4 rivets and 
shear 1 rivet. 

Values for calculations then equal : — 

111,562.5 pounds to break plate between holes. 

205,200 pounds to shear 9 rivets. 

206,460 pounds to crush in front of 5 rivets. 

160,000 pounds to crush in front of 4 rivets and shear 1 rivet. 

Select smaller value or weakest part of joint = 111,562.5 
pounds. 

Strength of solid plate = 

outer pitch of rivets, 5^ = 5.125 
thickness of plate, ^ = .4375 
25625 
35875 
15375 
20500 



2.2421875 



RIVETED JOINTS 95 



tensile strength of plate = 60,000 
2.24 
240000 
120000 
120000 



134400.00 

134,400)111562.5(.8307 = 83.07 percent, strength of 
1075200 joint. 

404250 
403200 



1050000 
940800 



CHAPTER IV. 

HEATERS, 

What is a heater? 

A heater is a tank where the exhaust steam from the 
engine passes through to heat the water on the way to the 
boiler. 

Describe them. 

There is an open heater and a closed heater. A closed 
heater is one in which the steam passes through between the 
shell and a brass coil which the water passes through to be 
heated, then to the boiler. 

An open heater is one in which the water and steam mingle. 
The pump is between the heater and the boiler and below the 
heater, as the pump will not lift hot water. 

A closed heater is between the pump and the boiler. 

How may you know if a closed heater leaks? 

Where the exhaust goes out of doors, you may notice an 
excessive amount of water with steam, also from the drip 
you will notice much water escapes. If heater leaks, the 
pump will run faster. A by-pass on heater is to pass water 
around the heater to boiler when heater leaks. 

The water supply to open heater is controlled by a float in 
the heater, shutting a valve from the supply when the water 
rises to a certain point in the heater. Heater should heat 
the water to 210° from a non-condensing engine. 

There are plants that have receivers where returns from 
buildings are pumped through heater to boiler. 

How hot can a heater heat the water? 

In a closed heater to about 130°, in an open heater 210°. 

The most economical way to heat water is by waste heat, 



HEATERS 97 

the exhaust steam from the engine. By this, in a first-class 
heater, the feed water can be heated to 210°. Differ- 
ence or saving between using feed water at 60° and, say, 200° 
is about 13 per cent, of the coal consumed in making steam. 

As a given weight of coal is used in both cases, about 
fifteen per cent, more effect will be obtained from the feed 
water at 200° over that of cold water. 

For every 10° added to the temperature of feed water by 
exhaust steam, nearly one per cent, of fuel is saved. 

What does it heat with? 

It heats the water with the exhaust steam from the engine. 
This exhaust steam goes into a heater through which the water 
is passed in a coil of pipe, and then after leaving the heater 
goes through pipes to heat the building in the winter. In 
the summer the back-pressure valve is opened to allow the 
steam to go outdoors. 

What are the different kinds of heaters? 

There are the open heaters and the closed heaters. 

What is an open heater? 

An open heater is one in which the steam and the water 
mingle. This heater is placed above the pump, so that the 
water may flow to the pump. On account of being hot the 
pump cannot lift it. The open heater heats water the 
hotter. 

What is a closed heater? 

A closed heater is one in which the steam and water do 
not mingle. The heater is placed between the pump and the 
boiler. If the heater leaks, there is a by-pass around the 
heater. In the exhaust pipe there is a back-pressure valve. 
This is weighted according to the back pressure desired for 
heating, usually about six pounds. 



98 



PRACTICAL STATIONARY ENGINEERING 




99 



DAMPER REGULATOR* 

The damper regulator is controlled by steam pressure from 
the boiler acting upon the rubber diaphragm and on the 
water beneath it. When the pressure increases in the boiler, 
the diaphragm rising lifts the weighted lever, which, as it 
lifts, opens a small water valve to admit water under city 
pressure beneath a piston in a small cylinder. This piston 
is then moved by the water pressure, and sets the damper 
through suitable chains. When pressure drops on boilers, the 
diaphragm, lever, and valve are reversed, and water ad- 
mitted to the other side of the piston, or water allowed to 
escape from the cylinders, which are single acting. The 
SPENCER is double acting. The damper closes a little at a 
time. If it sticks, the trouble is usually with a sticky valve, 
this valve being easily removed, and a new one substituted. 
The water before entering regulator passes through a reser- 
voir in which soft soap is placed to lubricate valve. 



HEATING SYSTEM, 

Describe a heating system. 

There are two systems of heating, direct and indirect. 
Direct heating is where the radiators are in the room to be 
heated. In indirect heating the radiators are in a room in 
the basement where air is heated. The radiators are in a 
room, almost always hung up to timbers, and are boxed in 
with galvanized iron, and a check or clamper connects with 
the outside air, which is controlled by hand. And sometimes 
the radiators are in a room in the basement where air is 
heated and then taken through flues to the rooms to be heated. 

What is a gravity system ? '. , • . 



100 PRACTICAL STATIONARY ENGINEERING 

In the gravity system of heating the steam is taken from 
the boiler in pipes to the radiators, and, after being con- 
densed into the water in the radiators, it flows back in an- 
other pipe to the basement into a pipe called the "return 
pipe/ 7 which enters the boiler below the water line. This is 
the double-pipe system. 

What is a single-pipe system ? 

In a single-pipe system the water condensed is returned from 
the radiators through the same pipe from which steam is taken. 
Single-pipe systems require the larger piping. The water is 
returned to the boiler, in the gravity system, by the water 
seeking its own level. The pressure in the return pipe being 
nearly the same as in the boiler, the water in the return pipe 
will level itself up in the return pipe and boiler. The height 
of the water in the return pipe in the cellar will be slightly 
higher than in the boiler, according to the loss in pressure in 
the steam passing through the radiators. On the main 
pipe a shut-off valve is placed. On the return pipe there is 
a check-valve, and between it and the boiler a shut-off valve. 
Were there no check-valve on return pipe and the main valve 
were to be closed, the pressure in the boiler would fill the 
system with water. In a heating system, if you have to shut 
off steam from the building, be sure and shut the return 
valve first, to prevent the water backing from the boiler into 
the return pipe; that is, if there is no check-valve on the re- 
turn pipe. Where a high-pressure boiler is used in a heating 
system, the water will not then flow back to the boiler by 
gravity, but is returned by a pump or return traps. If 
radiators are below the water line of the boiler, two traps 
are used, a common trap and a return trap, to return the 
water to the boiler. A return trap is placed 3 feet above 
the boiler. Return traps are used when radiators are below 



HEATERS 101 

the boiler. They work by allowing the full boiler press- 
ure to come on top of the water in the trap, and, when the 
pressure is equal, water will flow in the boiler. 

What is a Bundy return trap? 

In a Bundy return trap, when the trap is full, the bowl 
tips, opening the live-steam connection to the boiler, and full- 
boiler pressure enters through a pipe, the pressure between 
trap and boiler is equalized, and water flows into boiler itself, 
through a pipe and check-valve. When the trap is emptied, 
the bowl is tipped back by a counter-weight, the live-steam 
connection shut off, and a vent opened to allow the steam 
in the -trap to escape. There is then no pressure in the trap, 
and it will again receive water from the heating system. 
Water enters through a check and passes out through a 
check valve, passing into the trap through a trunnion. In a 
Pratt and Cady trap a float rises with the water and opens 
the live-steam valve, and, when emptied, closes the live- 
steam valve and opens the vent. Where radiators are 
below the water line, a common trap is used to keep radiators 
clear, and this common trap delivers its water into a return 
trap. There would be needed in the radiators 1 pound press- 
ure to every 2 feet the water must be lifted from the com- 
mon trap into the return trap. Where radiators are above 
the water line, but under pressure much lower than the boiler, 
return may flow direct into the return trap, but usually 
comes to a receiver, with a check on each pipe into receiv- 
ers, to prevent water backing up the different pipes if press- 
ure is less in one pipe than in the other. 

What is a vacuum system? 

When heating by exhaust steam in a large building, an air 
pump is placed on returns, to keep them clear and to keep 
back pressure off engine. This makes a rapid circulation, and 



102 



PRACTICAL STATIONARY ENGINEERING 



pumps the water into a receiver from which it is pumped into 
the boiler. Sometimes a small condenser or a jet of water is 
needed at the air pump to cool the returns. 

In heating with exhaust steam, there is needed on exhaust 
pipe a back-pressure valve and a stop-valve. If exhaust steam 
is not enough, add live steam through a reducing valve. Add 
weight to the back-pressure valve to get more back pressure, 
the usual amount being 5 to 7 pounds. 

The piping for exhaust steam is larger than for high press- 
ure, returns being trapped back to a receiver and pumped 
into boiler or wasted. 




Figure 23. 



TRAPS. 

The steam trap is used to drain the water out of radiators 
and not let the steam escape. The common kinds are the 
bucket trap, float trap, and expansion trap. In a bucket 
trap a bucket floats on the water in a trap, and, when the 
trap is filled, the water overflows into the bucket, sinking it 
• and opening the valve, and the steam pressure forces the 



HEATERS 103 

water out of the trap. When water is gone, bucket floats 
again, shuts the valve, and no steam can escape. 

What is the valve on the top of bucket for? 

There is a valve on top of the bucket traps which opens 
a by-pass which allows the water to be blown out of heating 
system without going through the trap valve. This is to 
clear the system of water quickly in the morning. When 
the steam comes, this valve is shut, and takes care of the 
water. All traps have some such device. These common 
traps will deliver the water against any pressure less than 
pressure in the radiators. When water from the trap is to 
be elevated, there must be a pressure in the radiators suffi- 
cient to do this, and this pressure will be 1 pound for 
every 2 feet of water to be raised. Heating returns some- 
times return to a tank and are pumped into the boiler. 

Where is the pump situated? 

The pump is below the tank, and is controlled by float 
inside the tank. When water gets high in the tank, this 
float rises and opens the steam valve to the pump, and pumps 
water from the tank into the boiler. If float leaks, fills with 
water, collapses, or drops off the stem, it will not work. To 
prevent collapsing, ribs are put on the float to stiffen.it. 

What if returns are hot? 

When returns are too hot for the pump, pump will run 
very fast and uneven, in which case open cold-water pipe to 
tank, and open drips on pump to let the steam out of water 
end. All traps have their valves at the lowest point of the 
water, and in a "Bundy" trap a pipe inside drips down into 
the water to keep the end water sealed, so steam cannot 
escape. The drips on water end are to drain water from 
cylinder to prevent freezing when pump is idle. They are 
shut when pump is running. 



104 



PRACTICAL STATIONARY ENGINEERING 



What is the pet cock on air chamber for? 
The pet cock on air chamber is to open to see if pump is 
pumping properly. If water is too hot for pump, pump will 




GURE 24. 



race badly. In this case open drips and cool water by open- 
ing city supply to tank. 

What is a float and expansion trap? 

The float trap has a float which rises with the water and 
opens the valve to let the water escape, and, when the water 
is out of the trap, float falls and shuts the valve. In expan- 



HEATERS 105 

sion trap the water in the brass pipe causes it to contract 
and open the valve ; and, when the water is gone and the steam 
comes, this pipe will expand and shut the valve. 



VENTILATION, 

How are school buildings heated? 

School buildings are heated by direct and indirect heating. 
Ventilation is obtained by forcing fresh air into the rooms after 
it has passed over indirect radiators in air room in the base- 
ment. The foul air is drawn out of the rooms by large 
heated chimneys or by fans. 

How is the temperature controlled? 

The temperature is controlled in indirect heating by pull- 
ing a chain in the inlet register in the room, this opening a 
mixing damper to allow cold air to mix with the warm air 
and partially shut off the warm air at the same time. If mix- 
ing damper is shut entirely, nothing but cold air will enter 
the room. At night the building is warmed by shutting the 
dampers in outlet to foul-air chimney or ventilating stack, 
opening doors from rooms to corridors and cellar, and opening 
door from cellar to cold-air room. Shutting outside windows 
in the cold-air room, the same air is then circulated around 
the building and over the radiators to keep the building warm. 
In school hours, door to cold-air room is closed, and the 
outside windows opened and fresh air 'taken from the outside. 

Cold-air windows must be opened wider in very cold weather, 
not shut up, in order to supply more air necessary to carry 
up more heat. The circulation is maintained in the ventilat- 
ing stack by fans, or in the gravity system by a small radiator 
at the base of the ventilating stack. 



106 



PRACTICAL STATIONARY ENGINEERING 



REDUCING VALVES. 



What is a reducing valve ? 
A reducing, valve is used to heat 
from a high-pressure boiler. 



building at low pressure 




Figure 21 



What valves should there be on this ? 

There should be a shut-off valve between it and the boiler, 
a steam gauge beyond the reducing valve, and a relief valve 
to prevent over-pressure if reducing valve fails. To increase 



HEATERS 107 

the pressure, screw down on spring or with lever reducing 
valve, add additional weights. 

There are two kinds of reducing valves. One is controlled 
by a weighted lever, and the other with a spring. They are 
to reduce a high pressure to a low in heating building. 



CHAPTER V. 
ENGINES. 

What is a high-speed engine? 

An engine whose piston runs at a velocity of 600 feet 
or more per minute at regular work. These engines are pro- 
vided with an automatic cut-off by means of shifting the 
eccentric across the shaft so as to reduce the eccentric throw 
and valve travel. This causes the valve to cut off the 
steam earlier. 

The eccentric, instead of being fixed upon the crank shaft, 
has an elongated slot, and is hung on an arm that is pivoted 
to its other end after the manner of a pendulum. 

How do you find the clearance? 

The head clearance is the distance between the piston at 
the end of the stroke and the cylinder head. The actual 
clearance is the whole space from the piston at the end of the 
stroke, including the ports to the face of the valve. To 
find the head clearance, put the piston at the end of the 
stroke and see how far across head is from the striking point. 
The striking points are marked on the glide at each end of the 
stroke. This shows where the cross-head would be if the 
piston touched' the head. Take twice the length of the 
crank and set it equally between the striking point, and the 
space on either end should be the head clearance. 

What is the position of an engine when on dead centre? 

The engine is said to be on the centre when the piston 
rod, cross-head, and connecting rod and crank are all in 
a straight line. 



ENGINES 109 

If steam were admitted at this time, it would have no effect 
on engine. It can have no effect to drive the engine until the 
piston is off the centre. It would be necessary to move the 
crank up or down, to produce such rotary motion; and this 
is accomplished in actual operation by the momentum of the 
fly-wheel secured to the shaft. The movement of the piston 
from one end of the cylinder to the other end is the stroke, 
and one complete circle of the fly-wheel is a revolution, mak- 
ing two strokes. 

Absolute Back Pressure. 

Usually taken at about 3 pounds for condensing engine and 
17 pounds for non-condensing engine. 
Piston speed used in modern practice is about as. follows : — 

Small stationary engine, 300 to 600 feet per minute. 
Large " " 600 " 1,000 " " 

Corliss " " 400 " 750 " " 

Locomotive, 600 " 1,200 " " 

How do you find the dead centre of an engine? 

Roll the engine in the direction in which it is to run until 
the approximate extreme travel is reached, then make a mark 
"D" on the guide at the end of the shoe. Now roll the 
engine over to opposite extreme throw, and make a mark 
"C" on the guide at the end of the shoe. Then measure 
in one-half of an inch from each mark, "M" and "N," and 
make another mark. Now roll the engine over till the end 
of the shoe is in line with one of your second inside marks, 
then make a mark on fly-wheel rim corresponding with a 
stationary mark on the floor. Now roll the engine over the 
centre till the end of the shoe comes back to this same in- 
side or second mark, then make a mark on fly-wheel rim cor- 



110 



PRACTICAL STATIONARY ENGINEERING 



responding with your stationary mark on the floor. Now roll 
the engine over to opposite end till the shoe coincides with 
the second or inside mark on that end, mark on fly-wheel 
rim corresponding with this stationary mark on the floor. 
Now roll the engine over the centre till shoe comes back to 
this second or inside mark, then make another mark on 
the fly-wheel rim the same as before. Now measure off one- 
half of this distance on the fly-wheel rim, or, in other 
words, find the centre between the two marks you have just 



^ 




£ Af J5 A 

/y£T//o2> cf /cc#r/A/q Sr/?/Jr/A/q Po/*/ts 

Figure 26. 



made on fly-wheel rim. Roll the engine till this centre 
mark corresponds with this stationary mark on the floor, 
then engine will be on dead centre on that end. Now meas- 
ure one-half of the distance between your other two marks 
on fly-wheel rim, roll the engine till this mark corresponds 
with your stationary mark. This will give you the dead 
centre on that end. 



ENGINES 111 

Clearance. 

What is clearance? 

When the crank is on dead centre and the piston at the 
end of its stroke, there is always a space between the piston 
and the cylinder head. The volume of the space plus the 
volume of the steam port leading into it is called the clear- 
ance. The piston is at the end of its return stroke, and the 
clearance is the volume of the space between the piston and 
the cylinder head, plus the volume of the steam port. In 
other words, the clearance may be defined as the volume of 
steam between the valve and the piston, when the latter is 
at the end of its stroke. The clearance of an engine may be 
found by putting the engine on dead centre and pouring 
in water until the space between the piston and the cylinder 
head and steam port leading into it is filled. The volume 
of the water poured in is the clearance. 

The clearance may be expressed in cubic feet, cubic inches, 
or percentage. 

If the compression were carried up to the boiler pressure, 
there would be very little, if any, loss, since it would then 
fill the entire clearance space at boiler pressure, and the 
amount of fresh steam needed would be the volume dis- 
placed by the piston up to the point of cut-off, the same 
as if there were no clearance. It is not practicable to build 
an engine without any clearance, owing to the formation of 
water in the cylinder clue to the condensation of steam, 
particularly when starting the engine, as water is practically 
incompressible. Some part of the engine would be broken 
when the piston reached the end of the stroke if there were 
no clearance space for the water to collect in. Usually the 
cylinder head would be blown off. Neither is it practicable 



112 PRACTICAL STATIONARY ENGINEERING 

to compress to higher pressure, as a general rule, for that 
causes too great a strain on the engine. Automatic cut-off, 
high-speed engines, with shaft governors, generally compress 
to about half the boiler pressure and have a clearance of 
from 7 per cent, to 14 per cent. 

How would you equalize your clearance? 

We would disconnect our cross-head, and proceed to get 
our striking point. We will push our piston to the end of the 
cylinder until it strikes the head, then make a mark on the 
glide even with the end of the shoe of the cross-head. Now 
we will push our piston to the opposite end of the cylinder 
until it strikes the head, and mark on guide even with the 
end of the shoe of the cross-head. This will give us our 
striking points. Now we connect our engine again, turn 
engine over on dead centre, make a mark at end of shoe, and 
measure to the striking point. Now we turn engine on oppo- 
site centre, make another mark at end of shoe of the cross- 
head. Take the measurement to striking point. This will 
show if there is any difference between the clearance of the 
head end and the crank end. If there is any difference, it 
would be caused by keying up on the cross-head or crank end 
of connecting rod. If key, gib and strap connections, this 
would shorten. To adjust, put shim between our stud end 
and our crank-pin box or cross-head box. The shim should 
be one-half of the thickness of the difference in clearance. 



Cut-off. 

What is the range of cut-off for a piston stroke? 

The range of cut-off is that part of stroke it is possible for 
the engine to cut off in. Engines having a single eccentric ; 
it is from zero to two-fifths stroke. Engines with a double 



ENGINES • 113 

eccentric, one-half stroke. In starting up these engines, take 
steam full stroke until they come up to speed. 
How do you equalize cut-off? 

To equalize cut-off, put engine governor in running position 
and adjust trips till valve is tripped at same point at each end. 
In setting the valve, governor rests on a collar or a stop- 
motion pin. After engine is started, stop motion is removed. 
This is so, if the belt breaks, the governor drops to the 
lowest position, and safety-cams should prevent valve being 
picked up and the engine from racing. 

How do you find the proper length of eccentric rod? 
To find the proper length of eccentric rod, roll eccentric 
to extreme of travel, and see if carrier arm and wrist plate 
works at an equal distance each side a centre line. 
What is the usual length of connecting rod? 
The usual length of connecting rod is six times the length 
of the crank. 

Why dees the piston travel faster on the head end? 
The piston travels faster on the head end than on the 
crank end. This is corrected on a single- valve engine by 
giving more lead on the crank end, and is due to the angu- 
larity of the connecting rod. 

The motion of the crank is steady, but the motion of the 
piston is not, as it stops at the end of the stroke, and moves 
faster at mid-stroke. The crank end of connecting rod moves 
in a circle instead of the straight line that the cross-head 
moves in, and for this reason the crank is half-way over, 
or vertical, when the piston is at more than half-stroke. 



114 PRACTICAL STATIONARY ENGINEERING 

PISTON. 

Describe a piston. 

There are two kinds, a solid and a built-up piston. The 
solid piston is of one piece, with grooves in its circumference 
to receive the packing rings. These "packing rings," or 
spring rings, are cast iron. They are thicker at the bottom 
and split, being a little larger than the cylinder. When in 
place, they spring out enough to keep the piston from leak- 
ing. If weak, they may be tightened by peening evenly 
inside with a ball-peening hammer. To remove piston rings, 
raise them carefully with a thin piece of tin all around, and, 
when out of the grooves, slide them off. 

A built-up piston consists of a spider, bull-ring, adjusting 
bolts, and packing rings. The spider is attached to the pis- 
ton rod, with a nut or key. The bull-ring is a solid ring and 
surrounds the spider. Between the spicier and the bull-ring 
are the adjusting bolts. These adjusting bolts are to raise 
the centre of the spider to keep it central in the cylinder, 
as the cylinder wears. The piston rod is tapered or has a 
shoulder on it, and is secured to the piston with a nut. Be- 
fore removing the piston, see that it is marked. If not, mark 
on the rod and cross-head, so it may be put back at the 
same point. Also see that the end of rod does not drop into 
cylinder as it comes off the stuffing box, for it will scar the 
cylinder. To adjust the piston, measure from counter-bore 
to centre of piston rod and adjust with adjusting bolts. 
Measure from counter-bore because it never wears. The 
counter-bore is so that the piston will ride over and prevent 
wearing shoulders in cylinder. 

Do not allow the packing to become hard and dry in the 
stuffing boxes, as under such circumstances it has a tendency 



ENGINES 115 

to cut and flute the rods. To pack piston rod, remove the 
old packing. There is a specially prepared packing, made of 
canvas and rubber . When the gland is drawn up with bolts, 
be sure and tighten squarely and not too tight at first. 

How can you tell if a piston is tight? 

Place your engine on head end centre, and open opposite 
drip. If it leaks, steam will come out. 

To see that a piston is steam-tight, put piston on crank- 
end dead centre, open steam valve, and with cylinder head 
off see if steam blows past piston or out of drips. 

How do you adjust piston? 

To adjust the piston, measure from counter-bore to centre 
punch-hole on a piston rod, and adjust with adjusting bolts. 
Measure from counter-bore because that part never wears. 

What is the object of the built-up piston? 

A built-up piston is used, so that, as the bottom of the 
cylinder wears, these springs bear against the packing rings 
and take up the wear. When piston is screwed in the cross- 
head, there are two holes tapped into the piston head. Put 
in long bolts and a bar, and turn piston in or out. 

What makes the piston rod heat? 

The piston rod must run centrally through the stuffing 
box at all times. If not, it will bind in the stuffing box 
and heat. The cross-head may be raised or lowered by 
bolts and wedges on the shoes of the cross-head. With a 
solid cross-head the guides may be shimmed. 

The Connecting Rod. 

What is the connecting rod? 

The connecting rod connects the cross-head with the crank. 
There are two kinds of connecting rods, the strap end and the 
solid end. The straps are secured to the stub ends either 



116 PRACTICAL STATIONARY ENGINEERING 




ENGINES 117 

by bolts or gibs, and the brasses are set up by a taper key 
or wedge. 

What is meant by angularity of connecting rod? 

The angularity of a connecting rod is a term that applies 
to its path of motion, which is during all parts of the stroke, 
except on the dead centre, at an angle to the line of engine 
centres. The crank-pin end of connecting rod moves in a 
circle instead of a straight line the cross-head moves in. 
The piston travels farther when on the head end than on the 
crank end, due to the angularity of the connecting rod. 

The direction of the variation is to cause the point of cut- 
off to occur later on the stroke, when the piston 'is moving 
from the head end of the cylinder towards the crank. 

The amount of variation caused in the two points of 
cut-off by the connecting rod depends upon the proportion 
that exists between the length of the crank and that of the 
connecting rod, which is greater than that of the crank. 

Solid-end Rod. 

What is a solid-end rod? 

Places for boxes are cut out of the side of the rod. A 
flange is placed on boxes to hold them in place with screws. 
On solid-encl rods a wedge instead of a key is raised by 
drawing a bolt. 

What is the effect of keying up on a solid-encl rod? 

Keying up lengthens the rod. 

You will find a number on the key, gib, strap, and. end of 
rod corresponding, and, when these parts are put together 
right, the same number will appear on the same side. In 
keying up a key-and-gib end, the key bears against the end of 
the slot in the rod and against the tapers of gib. In keying 
up, be sure that the boxes do not touch. This would be 



118 PRACTICAL STATIONARY ENGINEERING 

brass-bound, also key-bound; that is, where the key is down 
so far it fills the slot in the strap and cannot be driven 
further. This shortens the connecting rod. Some straps 
are bolted on instead of having a gib. In this case the key 
bears against the bevelled outer end of rod on one edge and 
the other bears against the brasses, and in keying up moves 
the brass toward the pin: this lengthens the connecting rod. 
Some straps are bolted on instead of having a gib. In this 
case the key bears against the bevelled outer end of rod 
on one edge and the other bears against the brasses, and in 
keying up moves the brasses toward the pin. This lengthens 
the connecting rod. 

Key, Gibs and Strap. 

The key, gib, and strap are the most simple and effective 
mechanical devices employed for securing the connecting 
rod of steam engines to the wrist and crank pins and taking 
up the lost motion in the boxes, as they possess sufficient 
strength without extra weight of material, and facilitate 
quick and easy adjustment. Some make the thickness of 
both straps on the connecting rod one-half the diameter 
of the crank pin and their width about three-quarters the 
length of the pin; others make the width of their straps three 
times their thickness and the area of the cross-section at the 
mortise equal to the area of the smallest part of the connecting 
rod; while others still make them equal in strength to the 
weakest point in the piston rod, which they undoubtedly 
should be in any case. 

What is the most common kind? 

The most common kind is the key, gib, and strap. The 
connection between connecting rod and wrist pin or crank pin 
is made through removable brasses, adjusted to take up the 



ENGINES 119 

wear. The strap holds the brasses in place: it is slotted to 
receive the gib and key. The gib is wedge shape, and has lips 
on it to hold the strap on, and the key is tapered to take up 
wear. Some straps are bolted on, instead of a gib. In this 
case the key bears against the tapered end of the rod instead 
of on the end of the slot in rod. 

What is the effect of keying up a key, gib, and strap? 

Keying up on a key, gib, and strap-end rod shortens the 
rod. This changes the clearance in the cylinder, making 
run nearer the crank end than the head end. By putting a 
piston shim between the strap and the box merely raises 
the key. Now, if you do not wish to change the clearance, 
put a shim between the end of the rod and box. This 
lengthens the rod. 

Key Room. 

What would you do if crank pin or cross-head had run out 
of key room? How would you proceed to key either of these 
boxes ? 

In a case of this kind the slot in the strap has moved ahead 
until it comes even with the slot in the stub end. The key 
cannot draw it up any more. Now, if we should place a shim 
between our stub end of rod and our brass, it would give 
us the desired effect, but this would change our clearance in 
the cylinder. So to avoid affecting our clearance, which is 
all right, we will place a shim between our strap and our brass. 
This will bring our strap back, and our key can take up anew. 

Eccentric. 

What is an eccentric? 

An eccentric is substantially a crank with its pin enlarged 
in diameter so as to enclose the shaft on which it is placed. 



120 PRACTICAL STATIONARY ENGINEERING 

It gives exactly the same motion that would be obtained from 
an ordinary crank of equal throw. 

What is meant by throw of the eccentric ? 

The term "throw of eccentric " is understood to be the same 
as the travel it imparts to the valve, and which is understood 
to be equal to the width of both steam ports with the lap 
added. 

What is meant by angular advance of the eccentric? 

Angular advance of the eccentric means the angle at which 
it stands in advance of that which it would occupy if the 
valve were in the centre of its travel and the crank at its 
centre. 

The eccentric consists of what? 

The eccentric consists of a strap, bolts, and rod. The strap 
conveys the motion of the eccentric to the eccentric rod. The 
strap must not bind the eccentric, or it will heat. If loose, 
it will pound. The eccentric is flanged to receive the strap. 

How do you take up the wear on the eccentric ? 

By putting in a thinner shim. 

What makes the eccentric heat up? 

If stuffing box on valve stem is too tight, bringing heavy 
load on eccentric, eccentric may heat. The eccentric must be 
kept well oiled. The eccentric is sometimes called a cam, 
which is erroneous. A cam is used to obtain a motion differ- 
ent from that which can be obtained from a crank. The 
term u cam," when used without qualification, is indefinite, 
and conveys no impression of its precise form of function. 

The position of the eccentric ahead of crank will be 90 
degrees plus the lap and lead. In following the crank, it will 
be 90 degrees minus the lap and lead. 

An engine having a single valve, or where the valve is 
controlled by the governor, takes care of admission as well as 



ENGINES 121 

the cut-off; an engine having a slotted eccentric is used where 
the governor is between the shaft bearings where an eccen- 
tric must be used. Weights move in as the load increases, 
and eccentric moves away from the shaft, or an overhang- 
ing pin is used where the wheel is outside the bearing of 
the shaft, a connecting rod from this pin operating the valve. 

A loose eccentric is used only with a riding cut-off engine, 
where the lead is taken care of by the fixed eccentric, the gov- 
ernor controlling only the cut-off. These governors are 
called fly-wheel governors because the governor is in the fly- 
wheel and acts directly upon the eccentric that moves the 
valve which positively opens and closes the steam valve, 
automatically changing the cut-off according to load. They 
operate a single balanced slide valve or a piston valve. 
The weights fly out as the speed increases, throwing a slotted 
eccentric nearer to the centre of the shaft, decreasing the 
travel of the valve and making an earlier cut-off. 

The eccentric is not fastened to the shaft, but is connected 
by links to weighted levers, pivoted on the arms of the gov- 
ernor wheel, and these weights are controlled by springs. 
As the speed increases, the centrifugal force of these weights 
overcomes the tension of the springs, and the weights fly out, 
and the links throw the eccentric toward the centre of the 
shaft, changing the throw of the eccentric and the travel 
of the valve, and making an early cut-off. When the load is 
increased, speed decreases, and the reverse of this operation 
takes place. The speed of these engines is changed by chang- 
ing the tension of the spring or adding weights to the gov- 
ernor. 

There are four types of these engines. The loose eccentric 
fits the shaft, and can be rotated around it. A slotted 
eccentric has a slotted hole in it, where it surrounds the 



122 PRACTICAL STATIONARY ENGINEERING 

shaft, and can be swung across the shaft, also an over- 
hanging and double eccentric. 

With single valve the compression changes with every 
change in load, increasing with a light load. When the load 
is lighter, cut-off is earlier, compression greater, and release 
earlier. With heavy load, cut-off is later, compression less, 
and release later. 

The object of using a slotted eccentric is to keep the lead 
constant for all changes in cut-off. 

Compound Engine. 

To obtain the advantages of a high pressure and at the 
same time avoid the loss due to cylinder condensation as 
much as possible, the steam may be allowed to expand in two 
or more cylinders. When the expansion takes place in two 
cylinders, the engine is said to be compound. If the expan- 
sion takes place in three cylinders, the engine is said to be 
triple expansion, and, in four cylinders, quadruple expansion. 

There are two types of compound. When one cylinder is 
placed behind the other, the engine is called a tandem com- 
pound. When the cylinders are placed side by side and the 
piston rods are attached to separate cross-heads, cranks 
90 degrees apart, the engine is called a cross compound. 
If both pistons are attached to the same cross-head, the en- 
gine is called a twin compound. The engines may be con- 
densing or non-condensing. 

In any compound engine, without a receiver, the two 
pistons must begin and end their stroke at the same time, and 
the two cranks must be together or placed 180 degrees apart. 

Receiver pressure is usually 10 to 15 pounds, and may be 
increased by cutting off earlier in the low-pressure cylinder 
or by cutting off later in high-pressure cylinder. 



ENGINES 123 

Cutting off earlier in low-pressure cylinder makes that 
cylinder do more work. Steam taken in is of a higher press- 
ure, and makes the high pressure do less work by putting 
more back pressure on that cylinder. 

To make the engine do more work, cut off as late as you 
can, also cut off later on low-pressure cylinder, and add live 
steam to keep receiver pressure up. This is accomplished by 
taking live steam through a reducing valve from the boiler. 

If high-pressure cylinder breaks down, disconnect that side, 
and run with low-pressure cylinder by opening by-pass to 
cylinder. 

If the low-pressure cylinder breaks, disconnect that side, 
and let the steam blow through, and run the engine with 
high pressure. 

To start the engine when the high pressure is stuck on the 
centre, open by-pass to cylinder and pull the high pressure 
off with the low-pressure cylinder. 

To start when the load is heavy, let the steam into the 
receiver and get the power of the low-pressure cylinder with 
live steam. If one end of the low-pressure cylinder is dis- 
abled, block the valve, shut that end, and run the engine with 
high-pressure cylinder with one end of low pressure, then 
make the cut-off as late as possible on low pressure to keep 
receiver pressure down. Steam in the receiver is sometimes 
superheated with live-steam. Receiver has a drain pipe to 
carry off condensed steam. 

A receiver is supplied with live-steam connection from 
boiler through a reducing valve. 

Receiver has a relief valve to prevent pressure getting 
too high. Receiver has a drip pipe, to drain the water out. 

If boiler pressure is raised and load added to the engine, 
enough to keep the old cut-off, then steam enters the re- 



124 PRACTICAL STATIONARY ENGINEERING 

ceiver at a higher pressure, and a greater weight will flow in, 
and, unless low-pressure cut-off is made later to correspond, 
the receiver pressure would rise; and, again, if we opened a 
separate live-steam pipe into receiver and added a supply 
to that coming from high-pressure cylinder, receiver pressure 
cylinder is cut off as late as possible, and if it is desired to 
get more work out of low-pressure cylinder by a later cut-off 
which would reduce receiver pressure, this pressure is then 
kept up by the supply of live steam to it. 

Compound engines are used for economizing in order to 
use steam of high pressure and expand it more. To divide 
the work of the high-pressure steam between the cylinders, 
and to get less cylinder condensation, a great deal of the hot 
steam is condensed when it enters the cylinder, and this is 
turned again into steam during the exhaust stroke, and passes 
out of exhaust pipe without doing any work. 

The ratio of expansion in a compound engine is the number 
of times the steam is expanded. 

Rule. — To 'find the ratio of expansion in any cylinder, not 
considering clearance, divide the total cylinder volume by 
volume of steam-in the cylinder up to the point of cut-off. 

Example. — An engine having a cylinder volume of 10 
cubic feet cuts off at a point where the volume of steam is 
6 cubic feet. How many times does the steam expand, or, 
in other words, what is the ratio of expansion ? 

10 cubic feet = volume of cylinder. 
6 cubic feet = volume up to cut-off. 

10-5-6=1.66. 

Rule. — To find the ratio expansion between compound cyl- 
inders, square the diameter of each cylinder, and divide the 



ENGINES 125 

square of diameter of low pressure by the square of diameter 
of high pressure. 

Rule. — To find the total ratio of engine, not considering 
clearance, divide the total cylinder volume of high-pressure 
cylinder by the volume of steam in cylinder up to the point 
of cut-off. 

Divide the volume of low-pressure cylinder by the volume 
of the high-pressure cylinder, and multiply these two products. 

Example. — A compound engine having cylinders 15 X 24 
and 40-inch stroke cut-off in high-pressure cylinder, at 9 inches 
what is the ratio of expansion, and total ratio of engine, not 
considering the clearance? 

15-inch cylinder area = 176. 

40= inches stroke. 



7068.0 = total cylinder volume in cubic 
176.7 inches. 

9 = inches point of cut-off. 



1590.3 



1590)7068(4.44 = ratio of expansion in high-pressure cylinder. 
6360 . . 



7080 
6360 
7200 



area 15-inch cylinder = 176.7 
40 



7068.0 = volume H. P. cylinder. 

area 24-inch cylinder =452. 4 

40= inches stroke. 



18096.0 = volume L. P. cylinder. 



126 PRACTICAL STATIONARY ENGINEERING 

7068)18096(2.5 = ratio L. P. to H. P. cylinder. 
14136 
39600 
35340 

4.44 

2.5 

2220 



11.100 = total ratio of engine. 

Valves. 

Describe action of a D slide valve. 

The various events which are governed by the D slide valve 
of a steam engine are as follows: — 

The live-steam period is that during which steam is ad- 
mitted from the steam chest into the cylinder, and the steam 
admitted during this period is termed live steam. 

The point of cut-off is that at which the valve closes the 
steam port and the admission of steam into the cylinder is 
stopped. Hence the cut-off is at the end of the live-steam 
period. 

The period of expansion is that during which the steam 
is allowed to expand in cylinder, and therefore begins at the 
point of cut-off, ends at the point of release. 

This point of release is that at which the valve opens the 
port and permits the steam to escape. The point of compres- 
sion is that at which the exhaust port is closed, which oc- 
curs before the piston has reached the end of its stroke. The 
steam that has not passed out of the cylinder is therefore 
compressed, the compression continuing until the valve 
opens for the lead. 



ENGINES 127 

What is lead? 

The lead of the valve is the amount the port is open to 
the live steam when the crank is on the dead centre. The 
point of admission is the amount that the port opens for 
the live steam to enter, and it follows that the lead and com- 
pression both act as a cushion, arresting the motion of the 
piston when it reaches the end of the stroke. Cushioning 
begins, however, at the time the exhaust port is closed enough 
to arrest the escape of the steam, while compression begins 
when the valve has closed the exhaust port. 
What does a D valve do? 

A valve has four things to do each stroke: lead, cut-off, 
release, and compression. Each edge of the valve does two 
of these things. More lead is obtained by making steam 
valve open sooner in the stroke. Earlier cut-off is obtained 
by making steam valve close earlier in stroke. More com- 
pression is obtained by making exhaust valve open earlier 
in the stroke. This makes the exhaust valve close earlier. 
Eccentric slipping makes all things late. 

What is the effect of setting the eccentric ahead? 
To make all of the events earlier. With reference to the 
stroke, it makes admission earlier, and gives more lead. Cut- 
off and release are earlier, and the exhaust valves close 
earlier, giving more compression. Outside lap makes admis- 
sion later and cut-off earlier, the lead is diminished. If the 
eccentric is ahead, to give the same lead with the greater 
lap, we shall have a still earlier cut-off, earlier release and 
compression, and an admission as early as it was before. 
With the eccentric set back, the effect is the valve opens 
later, giving less lead, cuts off and releases later, the ex- 
haust ports are closed later, giving less compression. The 
lap reduces the rapidity and diminishes the range of cut-off. 



128 PRACTICAL STATIONARY ENGINEERING 




Figure 28. 

Showing the valve in mid-position, 
S = steam lap. 
E = exhaust lap. 
S. P. = steam ports. 
E. P, = exhaust ports. 



ENGINES 129 

What is lap on the valve? 

The term "lap on the valve" denotes the amount the edges 
of the valve extend over the ports when the valve is in 
the centre of its travel. If a valve has f-inch lap, it is under- 
stood to extend f-inch beyond the ports when placed cen- 
trally over them. The object of lap is to secure the benefit 
to be derived from working steam expansively. Lap on the 
steam side is termed outside lap, while lap on the exhaust 
side is termed inside lap, on a common slide valve. 

What is the object of lead on the valve? 

The object of lead is to enable the steam to act as a cushion 
against the piston before it arrives at the end of the stroke, 
to cause it to reverse its motion easily, and also to supply 
steam of full pressure to the piston the instant it has passed 
dead centre. It varies in different engines from ■£% to T 3 g 
of an inch without regard to size or kind. The higher the 
speed and the more irregular the work, the more lead will be 
required for any engine. 

Lead on the steam end is a term applied to the amount of 
opening the valve has at the end of the cylinder into which 
the steam is entering. Lead on the exhaust end means the 
amount of opening the valve has on the end from w r hich 
steam is escaping. The name applies alternately to each 
end of the cylinder. 

How do you get additional compression? 

Advance the eccentric slightly or lengthen exhaust-valve 
rods. This gives lap on exhaust valves, also more com- 
pression, but makes the release of steam later. Exhaust 
lap on that account very limited. For fast-running engines 
additional compression is necessary, but the range of cut- 
off must not be reduced, as it lessens the power of the 
engine. 



130 



PRACTICAL STATIONARY ENGINEERING 




131 




132 PRACTICAL STATIONARY ENGINEERING 

Why do you give a valve lap? 

Giving a valve lap is intended merely that we may keep 
the port closed until the engine is on the centre. The lap on 
valve is the amount it overlaps the port when the valve is in 
mid-throw. Lap does not apply to the amount that valve laps, 
if the valve is not placed so as to overlap alike on both ends. 

Advancing the eccentric makes every action of the valve 
take place earlier in the stroke. 

Adding steam lap and then setting the eccentric ahead 
causes the port to be opened less and the cut-off to occur earlier. 

Adding exhaust lap will cause the release to be later, and 
the exhaust to close earlier. This gives greater compression. 

Taking away steam lap causes the valve to open the port 
earlier and wider, resulting in a later cut-off. Taking away 
same exhaust lap causes the exhaust port to be opened 
earlier and to close later, giving less compression. 

What is unequal steam lap? 

Exhaust lap is the amount the exhaust cavity overlaps 
the bridge. Unequal steam lap is given to cause the point 
of cut-off to occur at equal points in the piston stroke. 
There is more steam lap at the head end than at the crank 
end of the valve ; but unequal lap could be given in order 
to greatly vary the point of cut-off of the two-piston 
strokes. If such is desired, unequal exhaust lap may be 
given to equalize the point of release or to equalize the point 
of compression. 

What is the eccentric angular advance? 

The steam valves are given lap, and the eccentric angular 
advance on account of the exhaust valves. In case the ex- 
haust valves had no lap, release and compression would occur 
at the end of the stroke instead of before the end, as it should 
to obtain good distribution. Since the exhaust valve must 
have lap and there is but one eccentric, the steam valve must 



133 




134 PRACTICAL STATIONARY ENGINEERING 

have lap also. Therefore, the eccentric must have consider- 
able angular advance. 

Unequal steam lap is given to cause the point of cut-off to 
occur at equal points in the piston stroke. Unequal exhaust 
may be given to equalize the point of release or to equalize 
the point of compression. 

Which is the head end of cylinder? 

The head end of the valve, or the cylinder, is that which 
is farthest from the crank-shaft end, or that nearest to the 
crank shaft, being termed the crank end. 

What is cushioning? 

Cushioning begins at the time the exhaust port is closed 
enough to arrest the escape of the steam, and compression 
begins when the valve has closed the exhaust port. 

How do you find the area of steam port? 

Rule. — Multiply the length of stroke in feet by the num- 
ber of strokes per minute, and this product by the area of 
the piston. Divide this last product by 6000, which is the 
velocity of live steam in feet per minute. 

Example. — What should the area of steam port be for a 
10 X 12 engine, making 300 revolutions per minute? 

1 = 12-inch stroke. 

300 

300 

2 = strokes in one revolution. 
600 = number of strokes per minute. 
78.54 = area 10-inch cylinder. 
2400 
3000 
4800 
4200 . 



47124.00 



ENGINES 135 

velocity of steam = 6000)47124(7.85 = area of port in. square 
42000 inches. 

51240 
48000 



32400 



The port opening is designed for a constant speed of piston. 
But it is a fact that on the head end the piston moves much 
faster than on the crank end. When piston starts from 
crank end, it is slower and moves more rapidly after mid- 
stroke. The movement is first a rapid one and then a 
slow one. This is clue to the angularity of the connecting rod. 

The object of giving compression is to form a cushion for 
the piston, to stop it and carry it easily over the dead centre. 
The piston and its cross-head comes to a full stop twice in 
every revolution. 

Why do you use a slotted eccentric ? 

The object of using a slotted eccentric is to keep the lead 
constant for all changes in cut-off. 

D Valve. 

The ordinary D slide valve is subjected to a great pressure 
by the steam on its back. Thus, if a large engine, the valve is, 
say, 10 inches long by 12 inches wide, and the boiler pressure 
is 90 pounds. The pressure on the back of the valve is 
10 X 12 X 90 = 10,800 pounds. This great weight causes the 
valve seat to wear very fast. 

To obviate this, a balanced valve is employed. The plate 
and valve is ground to a perfect fit, and no steam can get on 
the back of the valve. The flat plate is called a pressure 
plate. The valve slides under this with a perfect fit. There is 



136 PRACTICAL STATIONARY ENGINEERING 

a spring pressing on the valve to keep it to its seat. The 
valve would still be unbalanced from beneath, steam filling 
the steam ports, pressing upwards against the valve, and 
forcing it against the pressure plate. 

To counteract this, recesses having the same width and 
length as the steam ports are cut into the pressure plate, and 
steam is allowed to enter each, and they are exactly opposite. 

What other advantage in a balanced valve and eccentric? 

The governor parts are made much lighter. 

Why do you cut off steam in a cylinder? 

The object is to use steam economically by cutting off the 
supply to the cylinder at such a point that, when steam is 
exhausted, it has expanded until there is no pressure in it. 



TO SET THE COMMON SLIDE VALVE. 

If the principles are understood, there should be no diffi- 
culty. The object is to make the valve travel equally each 
way from mid-position. This is what is meant by squaring 
the valve. 

First take off the steam-chest cover, then loosen the eccen- 
tric and revolve to extreme throw on head end, and note 
how much the valve laps over the port. A good way is to 
mark with a pencil, then revolve the eccentric to the oppo- 
site throw, note the lap on this end, and, if you find that the 
valve has travelled, say, \ inch farther on this end, shorten 
the valve spindle by nuts one-half of that amount, which 
will be \ inch. This will pull the valve \ inch towards the 
desired end and cause its displacement to be equal each way. 

Next revolve the engine to head-end dead centre, and give 
the eccentric the proper angle of advance. Give the valve 
A- lead, fasten the eccentric at this point, revolve the en- 



ENGINES 



137 




138 



PRACTICAL STATIONARY ENGINEERING 



gine to opposite throw dead centre, and see if you have the 
same lead on that end. If not, adjust by nuts on valve stem. 
Now, if you find that you have no lead, advance your ec- 
centric till you have the proper lead. With this properly 
done, your valve is set. 

The indicator should be freely used, and changes made to 
correct the defect shown on cards. 




Figure 33. 
Governor and Cams. 



139 




Figure 34. 



140 PRACTICAL STATIONARY ENGINEERING 

VALVE SETTING FOR THE PUTNAM ENGINE. 

What peculiarity is noted on a Putnam engine? 

It has poppet valves, balanced type, the two inside 
valves for steam and the two outside valves for exhaust, 
The ports in this engine are extended below the cylinder 
bore, so that the raising of valves by means of the trip shaft 
can be accomplished with one motion of this shaft. 

How are the valves operated? 

Each valve is operated by a separate cam attached to 
cam shaft, which in turn acts upon a lever on which the 
valve stem bears. Each valve has two seats. The cam 
shaft is driven by gears from the main shaft. 

How do you set the valves of this engine? 

Raise the governor balls as high as they will go, hold them 
in this position, then push in the steam valve levers far 
enough to allow the cams which operate them to be turned 
around, clearing the valves without lifting the valve. 

When the levers are in this position, tighten the set screw 
in the rocker arm at the bottom of the regulator, then lower 
the balls to their running position. See that the set screw 
on the side shaft is screwed up tight. Put the crank on dead 
centre near the cylinder. Beginning at steam valve No. 2 
(see cut), on head end make a scratch on valve stem -^ inch 
below the packing box, then turn the steam cam by hand in 
the direction indicated until it strikes the lever, raising same and 
valve stem -^ of an inch,, then make the set screw in cam tight 
when the valve is raised to the height as indicated by line. 

Next, while the crank is in the same position, take exhaust 
cam No. 4, — this is the outside nearest to the crank, — set that 
valve in the same manner as the steam valve, excepting 
that the scratch line should be made T 3 g of an inch below the- 



ENGINES 141 

packing box of valve stem, so as to raise the valve -j 3 g of an 
inch, at which point tighten as before. 

Next turn the fly-wheel in the direction it is to run till 
the crank reaches dead centre. Then set steam valve No. 3 
in the same manner as No. 2, excepting that you measure 
3*2 of an inch, letting the valve raise g- 1 ^ instead of j$ of an 
inch without moving the crank. Take exhaust cam No. 1 
and set the same T 3 g of an inch, in same manner as valve 
No. 4. Make set screws in cam tight. 

The caps to bearings of rocker-arm shaft which connect 
cam levers 2 and 3 are lined with leather, and are made so 
for the purpose of giving more or less friction to the shaft. 
In case the regulator becomes unsteady, tighten up slightly 
the two cap bolts on rocker-arm shaft. 




Figure 35. 
Riding Cut-off Engine. 

RIDING CUT-OFF ENGINE. 

What is the principal feature about a riding cut-off engine ? 

It has two valves and two eccentrics. 

What is the function of the main valve? 

It regulates the admission, release, and compression. 

What is the function of the rider valve ? 



142 PRACTICAL STATIONARY ENGINEERING 

It regulates the cut-off only, and has nothing to do with 
the lead, release, or compression. 

In what relation to the crank is the main valve eccentric set ? 

About 90 degrees ahead of the crank. 

In what relation to the crank is the rider eccentric set? 

About 180 degrees ahead of the crank, or about 90 degrees 
ahead of main valve eccentric. 

How do you set the valve on a riding cut-off engine? 

Loosen the eccentric, put it at extreme throw, and place 
valve square over the ports. Then mark with a pencil on the 
valve seat, and turn eccentric to the other extreme throw 
and note mark. Then,- if there is a difference, divide that 
difference, place your valve at that point, by the nuts on 
valve stem, and, if you are correct, the valve will travel 
an equal distance over the ports. Then put your engine 
on dead centre, and advance your eccentric till there is -^ 
inch lead. Then place your rider eccentric with your main 
eccentric, and place your valve square over the main valve, 
turn the engine over, and, if your work is right, the valves 
will travel together. Place the engine on dead centre, then 
measure off, say, 3 inches on the guides at each end, turn 
engine forward that amount on stroke, then turn the rider 
eccentric ahead till rider just closes the port. Now put your 
engine on other stroke the same way, and see if cut-off is 
alike. If not, adjust by nuts on valve stem by dividing one- 
half the distance. 

What is a left-hand engine? 

Standing at the cylinder end and facing the shaft, the fly- 
wheel is on the left side. 

What is a right-hand engine? 

Standing at the cylinder end and facing the shaft, the fly- 
wheel is on the right side. 



ENGINES 



143 




144 PRACTICAL STATIONARY ENGINEERING 




145 



CORLISS ENGINE, 

The Corliss valve gear is used in a large number of engines. 
It has four separate and distinct valves. Two of these connect 
directly with the steam chest, and are called steam valves. 
The other two valves connect direct with the exhaust chest, 
and are cylindrical in form and extend across the cylinder 
above and below. 

There is a disk or wrist plate, which is made to rock upon 
a stud by the eccentric rod connecting it with an eccentric 
on the crank shaft. 

There are four valve stems, which are connected to bell 
cranks. From the end of these cranks adjustable connect- 
ing rods, commonly called right and left, are made fast into 
wrist plate. Any one of the valves regulates independently 
of the other. As a consequence of this arrangement, the 
steam and exhaust valves have entirely independent move- 
ments, and the inlet ports may be suddenly opened full 
width by the quick movement of the steam valve. The 
advantage of this valve gear is that it permits an earlier 
cut-off with a greater range, a more perfect steam distribu- 
tion, and a smaller clearance space than is attained with the 
plain slide valve. 

Some valves have a T-headed valve stem, fitting into a 
slot in the end of . the valve, and these valves can be re- 
moved without removing the valve stem. The exhaust 
valve differs in appearance from the steam valve. 

There is a single eccentric and a double eccentric Corliss. 
A single has one wrist plate, the double two wrist plates. 
There is an eccentric rod, and a hook rod connecting rocker 
arm and wrist plate, and is lifted off in starting engine, so 
as to work the valve by hand. The crab-claw, or hooking 



146 PRACTICAL STATIONARY ENGINEERING 

latch, is held against the block on valve arm by a spring. 
When it moves forward, this crab-claw is intercepted by the 
cut-off cone, which disengages it from the block, and valve is 
then closed by a dash-pot. Right and left connections con- 
nect wrist plate and the valves, the governor balls rising or 
falling with the change of load, so as to disengage valve early 
or later in the stroke, according to the load. When governor 
balls rise, the cut-off is earlier. 

The Corliss engine is an automatic cut-off engine. 

How do you start a Corliss engine? 

In starting a Corliss engine, make sure that the governor 
is on the stop motion, so that the valve will be picked up 
when the engine comes up to speed. 



VALVE SETTING FOR CORLISS ENGINES. 

First look over the valve gear, and take up all lost motion. 
This is quite essential. 

Remove the valve chest bonnets on the side of the engine. 
You will find marks representing the edge of valve, also the 
edge of port. 

Then centralize the various parts, and equalize their move- 
ments. 

Roll the engine over, place piston on the dead centre. Put 
the governor in the average running position, loosen up the 
eccentric, and turn on the shaft to the extreme travel farthest 
from the cylinder, and wrist plate is at extreme of travel. 
Note mark on the hub and wrist plate. Roll the eccentric 
to opposite extreme of travel, and see if this mark on wrist 
plate corresponds with mark on the hub. If not, adjust 
eccentric rod till the centre mark on the wrist plate travels 
an equal distance each side of a centre mark "on the hub. 



ENGINES 147 

Place wrist plate in middle position, and hook up steam 
valves on both ends. Then adjust right and left, so steam 
valves will lap J inch or more, according to size of engine. 
At the end of valve on the side of engine will appear a mark 
on the valve showing the edge of valve and two marks on the 
seat, the lower mark showing the edge of the port, second 
mark representing the amount valve should lap over the 
steam port. Be sure wrist plate is in central position, and 
adjust steam valves. Then place exhaust valves line and line. 

Now advance eccentric till the valve has ^ inch lead. 
Fasten the eccentric to the shaft at this point. Roll the 
engine over to the head-end dead centre, and see if you 
have the same lead on that end. If not, adjust by the right 
and left. 

On most Corliss engine governors will be found a stop 
device, sometimes in the form of a loose pin or a removable 
collar. This device is for the purpose of preventing the 
governor from reaching its lowest position, for, when it 
reaches the latter position, the valve should not hook on. 
Should the governor belt break, the governor would stop, 
and reach its lowest position on the spindle; and, as the 
valves cannot hook on when in that position, the admission 
of steam to the cylinder is entirely shut off, and the engine 
will come to a stop. 

From the foregoing the stop at the lowest part of the 
governor spindle should be removed (as otherwise rendered 
inoperative as soon as the engine has attained full speed), 
and should again be placed in active position when about to 
stop the engine. 

We will again turn our attention to the exhaust valves, 
this time for the purpose of adjusting them for compression, 
as the exact amount can only be determined satisfactorily 



148 PRACTICAL STATIONARY ENGINEERING 

by trial. We will say that our engine is to have 2\ inches' 
compression; that is, the exhaust valves must be set so as 
to close the exhaust port when piston is within 2J inches of 
the end of the stroke. To do this, measure off 2J inches 
from each end of the guides, and make a line. Now turn 
engine in the direction it is to run until cross-head has 
nearly completed its outward stroke and has reached the 
line on guide. This marks the point of exhaust closure for 
that end. Then turn engine around in the same direction 
until the cross-head reaches the line at the opposite end 
of the guide. The opposite exhaust valve is then set in 
precisely the same manner. 

Roll engine on extreme of travel, and adjust the length 
of clash-pot rod till hook drops over block y 1 ^ inch. Put 
wrist plate on opposite travel, and adjust that rod same 
way. Now put engine on extreme of travel, and measure 
off 3 inches on the stroke. Then turn engine ahead that 
amount, and adjust the length of reach rod till that steam 
valve will just trip. Turn engine on the other stroke the 
same amount, and adjust that reach rod till that valve just 
trips. Then remove the stop-motion pin, allowing governor 
to drop clown. Roll engine over, and put eccentric at 
extreme travel, and adjust safety-cam till valve will not be 
picked up by the hook. Roll engine to opposite end until 
eccentric is at extreme travel, and adjust in the same man- 
ner. See that cams are not too far clown, as valve may not 
then be picked up on starting or when on stop-motion pin. 
Put governor in highest position possible, and turn engine 
over and see that valves will not open. 

Now place governor back on stop-motion pin or ring, 
and turn engine over. See if valves pick up. 

Adjust dash-pot rods by lengthening or shortening. 



ENGINES 149* 

DASH-POTS. 

The clash-pot is to close the valve rapidly after it is tripped. 
A common dash-pot has inside of it a piston, and a leather 
flap valve in the bottom. As piston rises, air is drawn in 
through the leather beneath the piston, and it closes by the 
weight of the piston, the air being forced through a small 
pet cock, bringing it gently to a stop and cushioning it. 

A vacuum dash-pot has 2 chambers, a vacuum and a 
cushion chamber, which is sufficient to close the dash-pot 
after the valve is released by the pressure of air outside. As 
piston rises, air is admitted into the cushion chamber, and, 
when clash-pot drops, the escape of air through the pet 
cock cushions the piston. If dash-pot works too slowly, 
open the cushion pet cock, or close it a little, if it works too 
quickly and pounds. With a vacuum dash-pot the vacuum 
is controlled by slight admission of air through a pet cock 
into vacuum chamber to partially destroy the vacuum. 
This air is expelled through a check-valve when piston drops. 

The speed of the engine may be changed by changing the 
weights on the governor. Changing its speed of revolution, 
increasing size of pulley on governor makes engine run faster. 
The gag-pot is on the side of the governor, to steady the 
governor and prevent hunting. It is filled with oil, and has 
a piston inside with a little hole drilled through it and an 
adjustable plug. The more freely the oil passes through 
this hole, the faster the governor will move. A heavy oil 
will make it move slower. To make an engine give more 
power, the governor cuts off later in the stroke; but outside 
of this speed of the engine may be increased, boiler pressure 
may be increased, or a larger cylinder. 



150 PRACTICAL STATIONARY ENGINEERING 

The clearance varies from \ to 3 per cent, in Corliss engines, 
and from 4 to 12 per cent, in high-speed engines. 



BROWN ENGINE. 

The Piston. 

The piston shown in cut is of the bull and packing ring 
type. The two packing rings are so placed as to travel 
just over the cylinder counter-bores, thus avoiding the wear- 
ing of shoulders at each end of the cylinder, and give abso- 
lutely tight working under all conditions without the use of 
auxiliary springs or other complications. 

Set screws in the piston head acting on the centre or bull 
ring, which in turn carries the weight of piston, allow an ac- 
curate centring of the piston at all times. 

The bull-rings of the large cylinder pistons are babbitted, 
furnishing the very best anti-wearing property. 

The piston rod is secured to the piston by a nut inside the 
follower, doing away with all danger of nut dropping off 
between piston and cylinder head, — the cause of more than 
one serious engine accident. 

The Valves. 

There are two steam and two exhaust valves of the flat 
multiported type, each set being operated by a separate ec- 
centric, and all independently adjustable. The steam valves 
are placed on the side and the exhaust valves at the bottom 
of the cylinder, the latter furnishing a perfect drain for all 
water. The valves and their seats are held in bored recesses 
provided for them within the body of the cylinder, and are 
located very close to the bore to reduce clearance to the 



ENGINES 151 

lowest point. Free access is given to both the steam and 
exhaust valves through the covers at the top and back of 
cylinder without disturbing the releasing gear or any other 
parts. The valves and seats, being both separate from the 
cylinder and easily removed, give an opportunity for inspec- 
tion and adjustment. 




Figure 38. 



Ample means are provided for quickly freeing the cylinder 
of any water which may enter, and, should there be an un- 
usual pressure due to large amounts of water entering with 
the steam, relief is given by the steam valves lifting or swing- 
ing from their seats on the ball nut I. This action pro- 



152 



PRACTICAL STATIONARY ENGINEERING 



vicles a much larger area for relief than would the ordinary 
pressure relief valves on the exhaust bonnets. 
The operation of the steam valves may be clearly seen 




Figure 39. 
, Section through Cylinder and Valves. 

by referring to cut, which represents the position the sev- 
eral parts occupy at the commencement of the piston 
stroke. 



ENGINES 



153 



The steel lifting block A connected to the lower arm of 
the steam lever B— the top of this lever being connected 
through the carrier arm and eccentric rod to the steam ec- 
centric—has just engaged the latch C, which is journalled 




Figure 40. 



on a pin on the steam-valve stem guide D. When the long 
arm of steam lever B is drawn toward the crank shaft by the 
eccentric, the block A is raised, which carries the latch and 



154 PRACTICAL STATIONARY ENGINEERING 

guide up with it and causes the valve to open the ports. This 
upward movement continues until the tail of latch engages 
the trip lever E, which causes the latch to release the block, 
when the valve immediately descends, dropping by its own 
weight, assisted by the steam pressure on an area of valve 
stem and being cushioned by the dash-pot F, which move- 
ment closes the ports, giving a very sharp cut-off. As no 
springs or vacuum pots are made use of to effect this closure, 
the closing effort is constant at all loads, and the cut-off takes 
place with very little noise and without jar to the valve gear- 
ing. Any desired degree of cushion may be secured on the 
dash-pot by means of taper pin H, which may be turned 
to open or close vent-hole in bottom of dash-pot. The 
closing of the steam valves imposes no work upon the 
governor. The trip lever E is carried by the trip shaft G, 
which is connected to and actuated by the governor. 

The exhaust valve mechanism is operated in an entirely 
new manner. 

The exhaust sliding bar A, which is connected through the 
carrier arm and eccentric rod to exhaust eccentric, is con- 
nected by link B and exhaust lever C to the exhaust-valve 
stem guide D, which is connected by the valve stem E 
to the exhaust valve. By this arrangement the movement 
of the valve is concentrated at the points of opening and 
closing, giving a long pause between, which results in a free 
exhaust and absence of back pressure, both of the greatest 
consequence in the case of the low-pressure cylinder of a 
compound engine. 

Separate eccentrics being used for steam and exhaust 
valves, allow separate adjustment for each, and give the 
wide range of cut-off and compression desirable for com- 
pound engines. Valves have short motions, and in conse- 



ENGINES 155 

quence the engines may be run at high speed, making them 
suitable for electric work, and yet have the economy due to 
the drop cut-off and four independent valves. Valves are 
closed positively in case the stem is packed too tight or 
for any reason they do not act properly. 




Figure 41. 
Exhaust Valve Mechanism. 



SETTING THE VALVES OF THE NEW 
BROWN ENGINE. 

When about to set the valves of the "Brown," the first 
requisite is the proper adjustment of the four valve stems to 
secure the necessary lap on each valve. 

Eeginning with the steam valves, remove guide box A 
(Figs. 40-41), and on valve-gear bracket a scratch mark B 
prick-punched at each end will be found. Now disconnect 
dash-pot connections from steam-valve stem guide D, and 
allow valve to drop as far as it will go, and then adjust by 



156 



PRACTICAL STATIONARY ENGINEERING 



turning valve stem in or out of valve nut until the distance 
between scratch mark B on valve-gear bracket and bottom 
of brass drip cup C is the exact width of steel gauge, or J 
inch. Then make stem fast to guide by means of nuts at E. 




Figure 42. 



The dash-pot stem G should then be adjusted until the 
top prick-punched scratch mark on guide D just shows above 
the top of guide box. Tighten nut on dash-pot stem. Make 



ENGINES 157 

these adjustments on both steam valves. Now turn the full 
side of steam eccentric on the dead centre farthest from 
the cylinder, having first seen that the dash-pot on crank- 
end steam valve is properly seated. When the eccentric 
occupies the dead centre, the lifting block A on crank end 
should then have just engaged the latch, with perhaps ^ 
inch clearance. If this is not the case, the eccentric rod 
should be adjusted until this clearance is obtained. When 
the eccentric occupies the dead centre nearest the cylinder, 
see that the foregoing conditions are fulfilled at the head, 
or end, of the cylinder farthest from the crank shaft. If 
such is not the case, adjustment must be made by the right 
and left rod connecting the two steam levers until proper 
clearance is obtained, on the head end. 

Now have the eccentric turned around on the shaft, and 
see that both valves are alternately raised an equal distance, 
which will be the case if the adjustments have been properly 
made. . 

Place the crank and the full side of the eccentric on the 
dead centre nearest the cylinder. The lifting block should 
have now just engaged the latch on head end. Have the ec- 
centric turned around on the shaft in the direction in which 
the engine is to run until the valve opens the ports the amount 
of the lead, which should not exceed q\ inch, unless it is 
positively known that the engine will run better with more 
lead. Have the eccentric fixed to the shaft at this point. 
The amount of lead may be accurately determined by remov- 
ing the upper head of the valve chests and measuring the 
lead by means of pieces of thin steel ^4 inch thick. The 
end of the steel strip is to be placed against the valve seat 
while the eccentric is being slowly turned around on the 
shaft. As soon as the strip enters the port, the valve will 
have opened ^ inch. 



158 PRACTICAL STATIONARY ENGINEERING 

Have the crank turned, in the direction it is to run, to the 
opposite dead centre, or crank end. 

The opposite steam valve should now have opened the 
port the amount of the lead, which it will do, provided the 
work of equalizing the movements of the valves has been 
properly done. If the lead is found to be correct, the ec- 
centric must then be permanently fixed in the position in 
which it will now be found on the shaft. 

The movement of the exhaust valves is now to be equal- 
ized in the same manner as for the steam valves. Marks 
will be found on the exhaust-valve stem guide D and guide 
box F showing position of valves, or, should the marks have 
become obliterated, the valves may be seen by removing 
the valve chest bonnets, and by the aid of pieces of thin steel 
their exact location may be determined, the same as with 
the steam valves. 

To determine the proper length of exhaust-valve stem, 
draw the valve forward, until it strikes. Screw the valve stem 
into the valve nut until marks H and / come together, then 
make nut fast at L. The lines J-K show the lap of valve. 
G and J, when together, show the opening line. 

To set the exhaust valves, mark the guides on the frame 
at each end, varying from 2J inches for the small engines to 
3 inches or 3 J inches for the larger ones from the full stroke 
of the cross-head. Then have the crank turned in the di- 
rection the engine is to run until the cross-head reaches one 
of these marks. 

Assume that the exhaust eccentric is on the dead centre 
nearest the cylinder and that the cross-head has reached the 
line on the guides nearest the cylinder. The exhaust ec- 
centric is now to be turned around on the shaft in the di- 
rection the engine is to run until the exhaust valve on head 



ENGINES 159 

end just closes the port, or until lines G and J come together. 
Fix the exhaust eccentric to the shaft at this point. Then 
have the crank turned in the direction it is to run until the 
cross-head reaches the line at the opposite end of the guides, 
when the exhaust valve at that end of the cylinder should 
have just closed the port also. 

If it does, the compression will then commence when the 
piston reaches a point from the end of the stroke corre- 
sponding to the distance marked on frame guides. 

The proper amount of compression and lead will have to 
be finally determined by an indicator after the engine has 
been started and run under working conditions. This we 
would recommend doing in every case. 

If an engine is to be run condensing, it will require more 
compression than an engine running non-condensing. 

After both sets of valves have been properly adjusted, 
attention should be given the governor. 

Loosen the governor springs until the weights can be 
readily moved from one position to the other by means of 
the central stem. Now press the stem in until the weights 
are in their outer position, and block them. Loosen set 
screw in governor connection lever on trip shaft, and move 
the trip lever E nearest governor, which is permanently 
fastened to the trip shaft, either toward or away from the 
latch, as the case may require, until the crank-end steam 
valve upon being raised will cut off when the second prick- 
punched scratch mark, on guide D, appears at the top of 
guide box. Then tighten set screw in governor lever on 
trip shaft. That is, with the governor weights in their outer 
position, the steam valve is only allowed to lift enough to 
just uncover the lap. The lap is the distance between the 
first and second scratch marks. 



160 PRACTICAL STATIONARY ENGINEERING 

Place the small handle on the front of governor in a vertical 
position and pull stem out until it is stopped by the handle, 
which will bring the governor weights to their inner position. 
The steam valve, now being raised, should not be cut off 
until the third prick-punched scratch mark shows at top 
of guide box, or T V inch less than the full throw of the 
short horizontal arm of steam lever B. The movements 
of the two steam valves may now be equalized by means of 
the taper pin L, in trip lever of head-end steam valve. This 
acts as a taper key. By loosening set screw and driving pin 
in, the cut-off is shortened. By driving out, the cut-off is 
lengthened. 

Setting the safety -stop. With the small safety -stop 
handle in a horizontal position and the central stem pulled 
out as far as it will go, the governor balls are allowed to 
reach an extreme point beyond their inner governing posi- 
tion, which imparts to the central stem an extra -£% mcn 
motion beyond its working limit. Block the governor in 
this position. Now screw J in until lower end of pawl K 
strikes tail of latch C, and steel on upper end of latch is just 
thrown out of engagement with lifting block A. Make check 
nut tight on screw J. 

This adjustment being made on both ends of the cylinder, 
each valve should be raised two or three times to see that 
clearance has been properly given between steel on latch and 
lifting block, so that latch cannot hook on at this point. 

Thus, should the governor belt break or by any other 
cause the governor balls be allowed to reach their extreme 
inner position, the steam valves remain seated, thus cutting 
off any further supply of steam to the cylinder. This is a 
most efficient and positive device, and would be the means oi 
saving an engine from destruction, where a governor without 
some such device would be absolutely powerless 



ENGINES 161 

The safety-stop handle should always be in a horizontal 
position while engine is running, being moved to the vertical 
position just previous to shutting down. 



FLY-WHEEL GOVERNOR, 

How do you set the valve of an engine having a fly-wheel 
governor ? 

If governor is not keyed to the shaft, find its proper 
position by putting the engine on the head-end centre, having 
the slot in eccentric come at right angle to the crank. Move 
weights in or out, and see if valve moves. If it does, move 
the wheel back and forth till you find the place where you 
can move the weights in and out without moving the valve. 
Fasten the valve there, and give the engine -^ lead on the 
head end by adjusting the valve stem or eccentric rod. Put 
on opposite centre, and note lead, if more, should not be 
changed. It should not be less on the crank end than the 
head end. Block out governor to see if cut-off is equal. 

What is a throttle governor? 

A throttle governor is placed on the steam pipe, and gov- 
erns engine by checking or throttling the pressure of steam 
as it enters the steam chest; but the point of cut-off does 
not change with a throttle governor, although the steam 
pressure in cylinder changes with the load. 

What is an automatic governor? 

An automatic governor does not change the steam press- 
ure entering the cylinder, but changes the point of cut-off 
with every change of load. 

What is the rule for finding the size of governor pulley, 
having given revolutions of engine, size of pulley on shaft, 
and revolutions of governor? 



162 PRACTICAL STATIONARY ENGINEERING 

Rule. — Multiply the diameter of governor pulley by the 
revolutions of engine, and divide the product by the revo- 
lutions of governor. 

Example. — It is required to change the speed of an engine 
now running 85 revolutions to 132 revolutions. The governor 
runs 110 revolutions. Pulley on crank shaft 10 inches 
diameter. What size pulley must be used on governor shaft? 

132 = revolutions of crank shaft. 

10 = diameter pulley on crank shaft. 
1320 
revolutions of governor = 110) 1320(12 = inches diameter 

110 pulley. 

"220 
220 



Example. — An engine having a governor running 110 revolu- 
tions, driven by a 12-inch pulley on governor shaft, what size 
pulley must be placed on crank shaft to make engine run 
132 revolutions per minute? 

110 = revolutions of governor. 
12 = diameter of governor pulley. 
220 
110 



1320 



revolutions of engine = 132) 1320(10 = inches diameter of 
132 pulley on crank shaft. 



163 



LUBRICATOR. 

How is the piston lubricated? 

The piston in the cylinder is lubricated through a sight- 
feed lubricator attached to the steam pipe. In filling the 
lubricator, all valves are closed. Open drip at bottom to 
let the water out. Removing filling plug at top of cup, the 
oil will show in the glass. The lubricator has connection 
with the steam pipe about two feet above the cup : the feed 
is opposite the cup, the steam pressure being alike at each 
opening. To overcome this, greater pressure is obtained 
by the' weight of water which is condensed in the longest 
upright pipe. The weight of this column of water gives 
the additional moving force in excess of the steam press- 
ure; and, to start the oil and lubricator feeding, this pipe 
must be full of water, or lubricator will not feed. 

Lubricators sometimes have but one connection with the 
steam pipe. In this case the water displaces a certain amount 
of oil which flows into the steam pipe. 

The feed, or drops, per minute is regulated by a small 
valve. 

The average feed is one or two drops per minute. 



CRANK PIN. 

To determine whether a crank pin is in line with the 
centre of the cylinder or not, put on the connecting rod, 
and key the boxes up snug on the pin. Then disconnect 
the rod from the wrist of the cross-head, and move the crank 
round; and, if the rod maintains a central line in whatever 
position the crank may be placed, the crank pin is in line 
with the centre of the cylinder. This test will also serve 



164 PRACTICAL STATIONARY ENGINEERING 

to prove the correctness of the boriDg of the pin boxes. If 
they are not bored exactly at right angles to the centre line 
of the rod, troubles similar to those caused by an untrue 
pin will ensue. Another oversight not generally thought 
of, and which causes much trouble with the crank pin, is 
that in planing off the stub end of the connecting rod more 
is planed off on one side than the other. As a result, every 
time the rod changes its position, the boxes will pinch on 
the crank pin, and cause undue heating. 



CHAPTER VI. 
PUMPS. 

What is a power pump? 

A power pump is one driven by a belt. It may be stopped 
by running belt off on loose pulley. A by-pass valve on 
suction side controls the amount of the water pumped. For 
hot water, pump should always be below the source of sup- 
ply, as a pump will not lift hot water. 

What is a single pump with high-pressure steam end for 
boiler feed? 

A single pump with high-pressure steam end has one steam 
cylinder and one water cylinder. The water end is double 
acting. That is, it is drafting water on one side of the 
piston while it is discharging on the other side. Conse- 
quently, it is both drafting and discharging at the same 
time, no matter which way it is travelling. A double-acting 
pump has one or more suction valves and one or more dis- 
charge valves at each end of the cylinder. Water enters 
the pump through the suction pipe into the suction chamber, 
through the suction valves into the cylinder, as the piston 
moves away; and, when the piston reverses its motion, the 
suction valves, through which the water enters, are closed, 
and the water is forced up through the discharge valves into 
the air chamber from which the discharge pipe is taken. 
The suction pipe is always the larger pipe, and is usually 
at the bottom of the cylinder. 

What is a double pump ? 

A double pump with high-pressure steam end has two 
steam cylinders and two pump cylinders side by side, and 



166 PRACTICAL STATIONARY ENGINEERING 




PISTON PATTERN WATER END. 




Figure 43. 



PUMPS 



167 



either cast together or connected together, so as to operate 
as one pump. It has one or more suction valves and one or 
more discharge valves for each end of each pump cylinder. 

What is a single-acting pump? 

Some power pumps are single acting on pump end; that 
is, they have valves at only one end of the cylinder. Con- 




FlGURE 44. 

Outside Packed Double Plunger Pattern. 

sequently, can only draft water when the piston or plunger 
is being moved away from the end of the cylinder where the 
suction valves are, and discharges the water on the return 
stroke. Some steam pumps have a partition in the middle 
of the pump cylinder and single-acting plungers running 
into and out of each end of the cylinder; but, as one plunger 
is always travelling toward the valves when the other is 
travelling away, the pump end, as a whole, is consequently 
double acting. 



Single Steam Pump in Detail. 
Describe the difference between a piston and a plunger 
pump. 



168 



PRACTICAL STATIONARY ENGINEERING 



In a piston pump the piston fills the whole diameter of 
the cylinder, while in a plunger pump the plunger does not 
fill the whole diameter of the cylinder, and only pumps 
such water as is displaced by the plunger. 

Plunger pumps of the so-called inside plunger or plunger 
and ring pattern, where the plunger is located within the 




Figure 45. 
Double Plunger Pattern. 



cylinder, and travels forward and backward in the parti- 
tion between the two ends of the cylinder, are not packed, 
the plunger sliding in a long sleeve, or lining. 

Outside plunger pumps — that is, those where the plunger 
moves in and out of the cylinder from the outside— are 
packed in the stuffing boxes through which they travel. 

How high will a pump lift water? 

When liquids are cold, a pump of design for good suction 
efficiency will lift water 20 to 25 feet vertical, according to 
the speed it runs. Horizontal run of piping and turns, or 
elbows, on suction side will reduce this in proportion to the 
friction loss which they cause. 



pumps 169 

What enables a pump to lift water from a well? 

By the action of the pump making a partial vacuum in 
the suction pipe, the atmospheric pressure forces the water 
up to the pump. 

How high will a pump lift water? 

The highest theoretical lift possible is 34 feet. 

What enables a pump to force water into a boiler? 

To force water into a boiler, the steam piston must be of 
larger area than the water piston. The area of the steam 
piston in proportion to the water piston varies according 
to the boiler pressure against which the pump delivers. The 
size and length of discharge pipe and the number of elbows, 
or bends, in the same also effect this. This ratio runs from 
2J to 1 for high-steam pressure up to as high as 13 to 1 for 
low-steam pressure, such as 5 to 10 pounds. 

Can a pump lift hot water? 

A pump cannot lift hot water. Therefore, it must be 
placed below the water supply. 

Can you tell when a pump is not pumping ? 

Pump will run fast. You get an unsteady stream of 
water from the pet cock on air chamber, if water is too hot. 
In this case, water must be cooled. Open city supply. 

Give some reason why a pump will fail to work. 

There are many things to prevent a pump from not pump- 
ing. Pump might be air-bound, too much air in air chamber, 
or steam-bound, which is caused by the water being too hot. 
Pipe might leak, strainer may be clogged, suction valves 
.have dirt under them or caught up, springs broken, valves 
may be worn out. A priming pipe enters suction pipe, if 
there is a foot valve on the suction pipe. If not, the priming 
pipe is connected to pump above the suction pipe and below 
the discharge valve. If suction pipe is too small for the 



170 PRACTICAL STATIONARY ENGINEERING 

pump, it will not deliver water enough to the pump; and 
pump will speed up and pump less water when running fast 
or if a suction is too long. 

Of what are the pump valves made? 

The pump valves are made of vulcanized rubber or brass 
for hot water and medium or soft rubber for cold water. 

Of what use is the air chamber? 

The air chamber on the pump is to cushion the water and 
give it a steady flow. Air chambers are not necessary on 
a duplex pump, as one side is always pumping. To start 
up a pump, open all drips, open suction and discharge valves, 
also steam exhaust, and turn on steam. When water is 
out of the steam cylinder, shut the drips. 

What style of packing is usually found on a pump? 

The steam piston does not need packing which is packed 
with a special metal-ring packing. The pump piston is 
usually packed with square canvas and rubber packing or 
braided hemp of special brand, as may be required to cor- 
respond to temperature of liquid being handled. To pack 
the piston on the water end, take off the follower plate, and 
remove old packing, replace new packing, breaking joints 
with the packing. Replace follower plate with head and nuts. 
When piston is packed properly, pump will run steady and 
pump a good amount of water. 

Pumps do not usually come with stuffing boxes packed, 
and should be packed with make and grade of packing best 
suited to the service on which the pump is to work. 



PUMPS 171 

SETTING PUMP VALVES. 

In general how would you set the valve of a duplex pump ? 

First we must find the middle position. Move the piston 
till it strikes the head, and make a mark on the piston rod 
opposite stuffing box. Move piston till it strikes the oppo- 
site head, and mark on the rod. Now get the centre between 
the two marks on rod, move piston back till middle mark 
is in line of the gland. The rocker arm of each side should 
be in mid-stroke. Valves should be set to just cover the 
ports, then the lost motion between the valves and nut on 
valve rod should be exactly equal. The steam valve of each 
cylinder is controlled by the action of the opposite piston. 

Describe the operation of a Deane pump. 

In the Deane single pump the piston in its travel operates 
tappets secured to the valve stem, operating an auxiliary 
valve which admits steam to one end and exhaust steam from 
the other end of a supplemental piston. This piston moves 
the main valve by direct pressure of steam on alternate 
end, which admits steam to the main piston. The length 
of stroke can be increased by putting tappets farther apart. 
The valve stem is connected to auxiliary valve. In moving 
this supplemental piston, it shuts off its own exhaust port, 
confining steam to cushion it and prevents it striking the 
head. It is prevented from rotating by a bolt through the 
side entering the slot in piston. If, however, the supple- 
mental piston fails accidentally to be moved, or to be moved 
with sufficient promptness by steam, the lug on the valve 
rod engages with it, and compels its motion by power derived 
from the main piston. 

How many ports has the steam cylinder of a Deane pump ? 

The Deane pump has seven ports, three for the main valve 
and four for the auxiliary valve. 



172 



PRACTICAL STATIONARY ENGINEERING 




Figure 46. 
Tappet Motion Pattern. 




NO^ 



Figure 47. 
Lever Motion Pattern. 



173 



DIRECTIONS FOR SETTING UP AND OPERATING 
PUMPS. 

In setting up a pump, the first requisite is to provide a full 
and steady supply of water or other fluid. To accomplish 
this, observe carefully the following points: — 

The suction pipe in all cases to be of sufficient size to supply 
water cylinder. If pipe is long, it must be larger, as the fric- 
tion due to unusual length will partly overcome the head 
due to the vacuum, and prevent a full supply. Make pipe, 
therefore, as short as possible, but make as few bends, and 
always make these as easy (i.e., long radius) as possible. 

In laying suction pipe, a uniform grade should be main- 
tained, thereby avoiding air pockets or summits. Grade 
the suction pipe toward the supply with a drop of not less 
than six inches in each 100 feet. It will be found economi- 
cal to have grade given by a civil engineer. 

The suction pipe and its connections must be tight, as 
a very small leak will supply the pump with air to its full 
capacity, so that little or no water will be obtained, accord- 
ing to the size of the leak. Before covering the suction pipe, 
it is recommended that it be tested with a pressure of not 
less than twenty-five nor more than fifty pounds per square 
inch, to discover any leaks. 

Wrought-iron pipe may be used for suction pipe of small 
sizes, but cast-iron flanged pipe is recommended for all 
sizes in which it can be obtained. When bell and spigot 
pipe is used, it should be laid with the direction of the cur- 
rent from the bell end towards the spigot end. 

All valves in suction and discharge pipes should be gate 
valves. 

A suction air chamber is an advantage on long or high 



174 



PRACTICAL STATIONARY ENGINEERING 




0H 



pumps 175 

suctions, and is particularly recommended for single pumps, 
on all fire pumps, and any pumps which are to run at high 
speed, especially for pumps of short stroke. 

A foot valve, under these conditions, insures a quick start- 
ing of the pump by maintaining the pipe full of water and 
free from air. When a foot valve is used, see that the area 
of its valve seat opening is not less than the area of the pipe. 

A strainer is always desirable, but not necessary when water 
is clear and free from foreign matter that will clog the valves 
and passages of the pump. The area of the strainer open- 
ings should.be at least four times the area of the pipe, to 
equalize the friction of water through the small openings, 
and because some of them are liable to become clogged. 
When strainers are used, they must be frequently inspected, 
and cleaned. 

Extreme caution must be exercised while pipe is being 
laid and pump connected, to prevent foreign matter, such 
as sticks, waste, and rubbish, from entering the pipe. Chips 
from threading pipe, sand, etc., will quickly cut the cylinder, 
piston, and valves of a pump, doing more damage than years 
of proper use, or perhaps entirely disabling it. 

A priming pipe connected to a supply above the pump 
or under pressure is a convenience for quick starting, and 
a necessity for a fire pump and most large pumps of all 
classes. 

Hot water cannot be raised to any considerable height 
by suction. Thick liquids and hot water should always 
flow to the pump by gravitation. 

The steam, exhaust, suction, and discharge pipes should 
all be as straight and as free from turns as possible. 

In connecting the steam pipe, proper allowance should 
be made for expansion. A gate throttle valve should be 



176 PRACTICAL STATIONARY ENGINEERING 

placed in the steam pipe close to the pump. Means should 
be provided for draining this pipe before starting the pump. 

A heater may be placed in the exhaust pipe to advantage. 

To prevent freezing, drain the pump by opening all cocks 
and plugs provided for the purpose. In piping from these 
drips, valves should be placed close to the pump cylinders. 
The steam and water cylinder drips should never be con- 
nected into the same pipe unless a check-valve is placed so 
as to close towards the water cylinder to keep it free from 
steam. 

Foundations suitable for the pump should always be 
provided. 

All pipes should be properly supported so as to relieve the 
pump flanges from undue strains. 

Keep the steam cylinder well oiled, especially just before 
stopping. 

Keep the stuffing boxes well and evenly filled with a good 
quality of packing. Don't screw them too tight. 

Let the steam end alone, if' the pump begins to run badly, 
until fully satisfied that there is no obstruction in the water 
cylinder, water valves, or pipes. 

The pump should be located, if possible, in a light, dry, 
warm, and clean place, and have good care. Do not over- 
look the importance of this last suggestion. 

Do not pull the pump apart to see what is inside, as long 
as it does its work well. 



177 



THE DEANE. 

Duplex Steam Pump in Detail. 




Figure 49. 
Piston Pattern. 



178 



PRACTICAL STATIONARY ENGINEERING 



LIST OF PARTS. 



1. Steam Cylinder. 


39. 


Leather Cup Packing. 


2. Water Cylinder. 


44. 


Water Piston, hd.Y for Patent 


3. Yoke. 




only, / Fibr's 


4. Valve Chest. 


45. 


Follower, / Ring 


5. Steam Cylinder Head. 


46. 


Inside Ring, etc., \ Packing. 


6. Inside Valve Chest Head. 


47. 


Fibrous Packing, / See No. 27. 


7. Outside Valve Chest Head. 


48. 


Seat, 1 


8. Steam Piston. 


49. 


Stem, 1 for Rubber 
Spring, | Water Valve. 


9. Valve Piston. 


50. 


10. Guide. 


52. 


Cover, J 


11. Tappet Arm, with bolts and 


51. 


Rubber Water Valve. 


nuts. 


75. 


Tappet Arm, \ 


12. Water Valve Plate. 


76. 


Inside Cross-head, I 


13. Water Cap. 


77. 


Inside Plunger, / ■ or 


14. Water Cylinder Head. 


78. 


Outside Plunger, \ Dou ble 


15. Water Cylinder Lining. 


79. 


Side Rods, ( P ^nger 


16. Main Valve. 


80. 


Piston Rod, | Pum P s - 


17. Auxiliary Valve. 


81. 


Outside Cross Head, / 


18. Air Chamber. 


84. 


Stem, ) 


19. Piston Rod. 


85. 


Spring, C ^ Metal Disc 
Seat, ) Valve ' 


20. Tappet. 


87. 


21. Tappet Key. 


86. 


Metal Disc Valve. 


22. Tappet Set Screw. 


88. 


Bearing Stand. 


23. Lubricator. 


89. 


Piston Rod Arm. 


24. Valve Rod. 


90. 


Lever. 


25-25-25-25. Drip Plugs or Cocks. 


91. 


Fulcrum Pin. 


26. Eye Bolt and Nut. 


92. 


Tappet Block Nut. 


27. Water Piston, complete with 


93. 


Piston Rod Link. 


packing. (See Nos. 44 to 47.) 


94. 


Link Pin. 


28. Bushing, j for piston Rod 


95. 


Piston Rod Arm Bolt. 


29. Gland, ^ gtuffi Box 


96. 


Piston Rod Arm Pin. 


30. Cap, ) 


97. 


Lever Pin. 


31. Nut, y 


98. 


Tappet Block. 


32. Flange Nut, y for Piston Rod. 

33. Check Nut, ) 


99. 


Gland for Stud Stuffing Box. 


100. 


Valve Rod Links. 


34. Cap, | for Valve Rod 

35. Gland, j Stuffing Box. 


101. 


Link Stud, Washer and Nut. 


102. 


Yoke Rods. 


36. Water Piston, head } for 

only, ! Leather 

37. First Follower, Cup 


103. 


Plunger Glands. 










38. Second Follower, J Piston, 







PUMPS 



179 



COMBINED MOVABLE SEAT 
AND AUXILIARY VALVE 




Figure 50. 
Section op Steam End of a Blake Single Pump 



180 PEACTICAL STATIONARY ENGINEERING 

In an ordinary engine the reciprocating motion of the piston 
is converted into a rotating movement of the fly-wheel by 
means of a crank. An eccentric secured to the shaft drives 
the valve. With the ordinary type of pump this means can- 
not be employed, as there is no rotary motion which can be 
used to actuate the valve. A difficulty arises in this con- 
nection from the fact that, when the valve is central, steam 
is cut off from the cylinder, and there is no momentum stored 
in a fly-wheel to force the valve in either direction to open the 
port. This difficulty exists in all pumps, and the means 
adopted to overcome it constitute the 'distinctive features 
of the Blake pump. In pumps, as in engines, the valve 
motion is derived from the stroke of the piston; and it is our 
purpose to describe the means of derivation employed, the 
methods adopted to obviate the ".dead-centre" difficulty, 
and the processes of setting the valve gear so as to secure 
the best results. 

Figs. 1, 2, 3, and 4 represent the steam end of the Blake 
pump. This is the arrangement of the boiler feed and press- 
ure pumps. First, we will consider the valve movement, 
without any regard to the gear by which it is accomplished. 

The main valve, which controls the admission and exhaust 
of steam from the main cylinder, is carried by the auxiliary 
piston, and moves on the back of the movable seat. This 
movable seat is shown in Fig. 4 in perspective, and the pas- 
sages A, B, C, serve as steam ports to the main cylinder; 
while the lugs GG' control the admission of steam to the aux- 
iliary cylinder and the holes HH' control the exhaust from 
that cylinder. 

With the valves in the position shown, the course of the 
steam is through live-steam passage N, through the port C 
to the right-hand end of the main cylinder, thus forcing the 



PUMPS 181 

piston over to the left. Now, when the piston nearly reaches 
the left end of the cylinder, the movable seat, by a means 
described later, is shifted over to the left, so that the lug G 
covers the port E, while the lug G' moves off from the port 
E' , thus admitting steam behind the auxiliary piston, at the 
left-hand side. At the same time the exhaust port K of the 
auxiliary cylinder is put into communication with the hole 
S which leads to the exhaust. The auxiliary piston is there- 
fore forced over to the right, and uncovers the port A to live 
steam. Near the right-hand end of the stroke the operation 
is reversed. That is, the movable seat, which is then at the 
left, is moved over to the right, assuming the position shown 
in Fig. 1. The lug G then uncovers the port E, while E' is 
covered by G '. This admits live steam to the right of the 
auxiliary piston. At the same time the hole H f in the aux- 
iliary valve or movable seat places K! and S in communica- 
tion, thus exhausting the steam from the left of the auxiliary 
piston. This drives the auxiliary piston over to the left, 
until it assumes the position shown in Fig. 1. 

The auxiliary piston is cushioned on steam, because the 
exhaust port is not out at the end of the auxiliary cylinder, 
and consequently there is steam imprisoned when the piston 
covers the exhaust, as shown at the left in Fig. 2. The main 
piston is cushioned on live steam, because the valve has 
lead; that is, the operation of admitting steam is performed 
before the piston reaches the end of its stroke. 

It will be seen that, if means are provided to shift the 
movable seat from one end of its travel to the other, the rest 
of the operation is automatic. Fig. 1 shows the valve gear 
provided for this operation. The piston rod is provided with 
a cross-head, the latter having a pin as shown. The frame of 
the pump is built with an upright piece, U, to which is pivoted 



182 PRACTICAL STATIONARY ENGINEERING 

at P a lever whose lower end is slotted and engages with the 
cross-head. The valve rod, which is secured to the movable 
seat, is provided with two collars, as shown. These collars 
are made of split nuts which work on a thread cut on the 
valve rod for a short distance on each side of their ordinary 
position. Between these two collars is a tappet, which is 
free to slide on the valve rod. The link shown connects the 
tappet with the lever. When the piston rod moves, the lever 
rotates about P, carrying the tappet with it; and, when the 
tappet strikes either collar, it moves the movable seat in the 
direction in which the tappet is moving. By placing the 
collars so that the tappet strikes them before the piston 
reaches the end of its stroke, the movable seat will be shifted 
in the required manner. 

No valve adjustment is required to be made inside the 
steam chest, and the only adjustment which can be per- 
formed is that of altering the distance between the collars, 
thus changing the travel of the valve, This is done by 
loosening the set screws in the collars and rotating the latter 
until they come to the required point. Changing the distance 
between the collars alters the length of the stroke. This is 
easily seen, because the action of the tappet in striking the 
collars is what admits and exhausts the steam; and, if the 
distance which the tappet has to travel is varied, the time at 
which the valve is actuated is varied, and the stroke varies 
as well. 

The adjustment of these collars is very simple, and can be 
performed while the pump is running. In adjusting them, 
it is desirable to make the stroke as long as possible and se- 
cure enough cushioning, for the shorter the stroke the greater 
the amount of clearance, and the steam required to fill the 
clearance is wasted on every stroke. 



pumps 183 

If the collars on the valve rod are not set at equal distances 
from the centre line of the lever when the latter is vertical, 
the movable seat will be reversed sooner on one stroke than 
on the other, and consequently the piston will travel further 
in one direction than in the other. 



THE MASON PUMP GOVERNOR* 

The Mason pump governor is to the direct-acting steam 
pump what the ordinary ball governor is to the steam en- 
gine. It attaches directly to the piston rod of the pump, 
and operates a balance valve placed in the steam pipe, 
thereby exactly weighing the amount of steam to the needs 
of the pump, and economizing the same. By using the 
Mason governor, you can instantly set or change your pump 
to any required speed, which will be maintained in spite of 
variation in load or steam pressure. As all the working 
parts of the governor are immersed in oil, the wear is re- 
duced to a minimum. It is largely used on vacuum pumps 
and all classes of pumps requiring a uniform stroke. 




Figure 51. 



Figure 52. 



CHAPTER VII. 

CONDENSERS. 

What is a condenser? 

It is a closed vessel in which steam is brought in contact 
with water or cooled tubes, and thereby condenses or re- 
duces the steam to water. 

What are the types of condensers? 

Surface and jet. 

Describe the surface condenser. 

The surface condenser consists of a shell nearly full of small 
tubes, ranging from f to | inch in diameter, and which are 
made fast to tube plate on each end. Through these tubes 
water is circulated. Between the inner and outer heads 
suitable partitions are made to keep the flow moving without 
disturbance of other currents of water. Steam is admitted 
to the top, and, coming in contact with the cooled tubes, con- 
denses or is reduced to water, and falls to the lower port of 
condenser. From there it is pumped to hot well. With this 
type of condenser are provided a circulating pump, which 
circulates or forces the condensing water through the tubes, 
and an air pump, which frees the condenser of water con- 
densed from the steam. This discharge, as stated before, goes 
to the hot well. The circulating pump's discharge is carried 
to a cooling tank, or, if the plant is located by a river or 
stream where clear water is available, it takes its suction 
and discharges to this source. In this type the steam and 
water never come in contact. 



CONDENSERS 185 

What particular advantage has this type of condenser? 

It can be used where the fresh-water supply is poor or lim- 
ited or where salt water is available for circulation. 

Why are tubes of small diameter used ? 

To obtain as much cooling surface as possible within the 
condenser shell. These tubes are made quite thin, usually 
about f 3 4 of an inch, so that they will not hold the heat 
given out by the steam. 

How are condenser tubes made tight in the plate ? 

By wood or sometimes paper ferrules, which fit the tubes 
and are driven into the tube plate, or by glands tapped 
into the tube plates with suitable packing to press against the 
tube, making a tight joint. 

What type of pump is almost always used with a jet con- 
denser ? 

A single-acting, vertical bucket air pump. 

Describe the action of a bucket pump. 

The bucket air pump is a single-acting pump. In fact, a pis- 
ton with valves fitted to it which closes on the up stroke and 
opens on the down, lifting a quantity of water equal to its 
capacity at each stroke of the engine. A dependent air 
pump is driven by the engine itself, starts and stops with 
the engine. 

The dependent pump is usually driven by a connecting 
rod from the crank pin, connected to the long arm of the 
lever, the short arm of lever operating the pump. A bucket 
pump has valves in the piston or bucket. The piston is at- 
tached to a large hollow piston rod called a trunk, and has 
the wrist pin at the bottom of this hollow piston or trunk. 
This trunk acts as a guide, and works through a stuffing box. 
The water passes from the bottom of the condenser, through 
a channel way, to the air pump, and, as the bucket descends, 



186 PRACTICAL STATIONARY ENGINEERING 

the water passes through the valves in the bucket, and, when 
the bucket rises, this water is forced through a set of valves 
in the delivery plate above. The valves in the bucket are 
called the bucket valves. The valves in delivery plate are 
called the discharge valves. To get at the valves and bucket, 
take off the hand-hole cover above delivery plate, then the 
bucket valves and bucket can be seen. The air-pump lining 
is made of brass. Bucket is kept tight by square hemp 
packing 7 or by wood packing, of blocks made of maple, about 
4 inches wide and J inch thick, like staves of a barrel. Be- 
tween the bucket and the wood, rings of rubber hose hold 
the packing out against sides of the cylinder. The trunk is 
packed like an ordinary piston rod. 

Describe a jet condenser. 

The jet condenser consists of a body casting, on the top of 
which the exhaust from the engine enters, and in its passage 
through comes directly in contact with a sheet of water from 
the injection main; then it condenses and falls to the base of 
the condenser, and is removed by the air pump. The spray 
or sheet of injection water is regulated by a hand wheel on 
top of condenser, and care must be taken to regulate the 
speed of air pump to handle this injection water, the con- 
densed steam, and the air brought in with the injection water. 

Could you use a surface condenser, in case of emergency, 
for a jet condenser? 

To enable a surface condenser to be used as a jet condenser 
in case of accident to the circulating pump, a pipe leads 
from the injection cock of the circulating supply pump into 
the bottom of the exhaust pipe or column, where it enters 
the condenser. This pipe is supplied with a spray or rose 
nozzle, which divides up the injection water and causes it 
to condense the steam as it enters the condenser. 



CONDENSERS 



187 




Figure 53. 



188 PRACTICAL STATIONARY ENGINEERING 

What is a vacuum breaker? 

It is an attachment fastened to the side of a condenser 
consisting of a float and air valve, and also as part of it a 
pipe connecting air valve to body of condenser, its purpose 
being that, if the water should rise above the safe limit, the 
float would be raised, which in turn would raise the air valve 
admitting air to condenser, thus breaking the vacuum and 
equalizing the outside and inside pressure and stopping the 
injection flow. 

Why are vacuum breakers necessary? 

Unless such an attachment is provided, the injection water 
would soon find its way back to the cylinder and cause damage. 
In some condensers the arrangement of injector neck will 
accomplish the same results. 

When vacuum is broken, what course does the exhaust from 
engine take? 

The vacuum being broken, the pressure will equalize and 
force open an exhaust valve which is so placed that, when 
condenser is in operation, it remains closed, but, when pressure 
is equalized, the exhaust forces open the valve and is allowed 
to go into atmosphere. This valve is usually of the swing- 
check type. When the cause is removed and vacuum is 
re-established, the pressure falls below the atmosphere and 
the valve is closed. 

Why are condensers used? 

In a non-condensing engine or an engine exhausting into 
atmosphere, the steam which has filled the cylinder during 
the stroke has to be forced out against the atmospheric press- 
ure or at about 15 pounds per square inch. 

By condensing the steam (which forms a vacuum), we 
relieve the piston of a greater part of this atmospheric press- 
ure, allowing it to return with but little back pressure. If 



CONDENSERS 189 

we take, say, 12 pounds per square inch from the back press- 
ure by condensing, we have practically added 12 pounds 
per square inch to the pressure forcing the piston. 

Give two reasons why a condenser will fail to work., 

The air pumps may not properly remove the air and water 
or there may be insufficient injection water. 

Explain the working of an injector condenser. 

The injector condenser consists of two conical nozzles, 
jointed by a straight neck and swelled at the upper end of 
the water nozzles. Within are the exhaust-steam nozzles, 
which form within the condenser a narrow, annular space 
for the entrance of the condensing water. The sides of the 
condenser are smoothly finished, as is the contracted neck 
below, to diminish the resistance of the water. When used 
in connection with a condensing engine, the air pump may 
be dispensed with, as steam of atmospheric pressure will 
flow into a vacuum at the rate of 1,600 feet per second. 
When the exhaust steam from the engine meets the thin 
film of water which enters by the annular space, it is instantly 
condensed. As the water passes down, the contracting 
outline of the condenser gradually brings it to a solid jet in 
the neck below, through which it rushes with a velocity due 
to its pressure. 

The air which has entered the condenser with the water, 
or through leaky joints or stuffing boxes, together with the 
uncondensed vapor, is thus drawn into a contracting, hollow 
cone of water, until finally expelled through the neck. This 
latter, being straight for a distance, is virtually the air pump, 
having a solid column of water moving at a high speed. 
This is the steam condensed, and the vacuum is formed by a 
single process, and with greater certainty than in any other 
w r ay. The air and vapor, having passed the contracted neck, 



190 PRACTICAL STATIONARY ENGINEERING 

enter the tapering nozzle below, and, expanding therein, are 
prevented from returning to the condenser above. 

The method of operation of the injector. condenser when 
the engine is started is as follows : The exhaust steam expels 
the air from exhaust pipe and condenser. Then a jet of cold 
water from a pump or tank creates a vacuum which may be 
maintained by a head of water 10 feet fall. The discharged 
water passes off at a temperature of 110°, when vacuum is 
equal to 26 inches of mercury. 



BULKLEY CONDENSER. 

Describe the action of a Bulkley condenser. 

The Bulkley condenser has a pipe, dropping 34 feet, which 
discharges water from the condenser. The weight of this' 
column of water 34 feet high more than overbalances the 
atmospheric pressure, and the water will flow from the con- 
denser into the air. If the injection water is within 20 feet 
of the condenser, the vacuum will lift the water into the 
condenser. If supply is lower than this, a pump must be 
used to force the water into the condenser. Between the 
injection pipe and the overflow is a cross pipe with a valve 
in it, which is used in starting up. To start up, open this 
valve, allowing the water to cross over into the overflow 
pipe, and shut this valve when vacuum enough is obtained to 
lift water into condenser. With this condenser, water can- 
not work over into the cylinder of the engine. 

How do you start a condensing engine having an inde- 
pendent air pump? 

Start up air pump first, to get up the vacuum, and then 
start the engine when ready. After engine is started, air 
pump can be speeded up, if needed, to keep up the vacuum. 



CONDENSERS 191 

Sometimes there is an atmosphere pipe from the exhaust 
pipe, so engine can be run either condensing or non-con- 
densing. This pipe has an automatic check-valve which 
will close itself when a vacuum is in exhaust pipe. Such 
an engine can be run non-condensing, and, when the air 
pump is started and vacuum obtained, and valve to the con- 
denser opened, and engine feels vacuum, then the check- 
valve will shut itself, and engine will be running condensing. 

In stopping an engine that is run with an independent 
air pump, shut down engine first, then shut down air pump. 

How do you start a condensing engine having a depend- 
ent air pump? 

Open forced injection as the engine starts, and, when 
there is vacuum enough to lift the water through the main 
injection pipe, open the main injection valve slowly, and 
shut forced injection. The main injection should then be 
opened as the engine comes up to speed. The danger in 
handling such an engine is in getting more injection water 
than the pump can handle. In starting, the pump is moving 
very slowly. In stopping an engine with the dependent 
air pump, be sure and partially shut injection as the engine 
slows down. If this is not done, water might be drawn 
into the cylinder, and head might be knocked out. 

VACUUM. 

How is vacuum maintained? 

The vacuum is maintained in the condenser by the exhaust 
steam being constantly condensed by either mixing with 
the cold injection water or by being brought in contact 
with the cooling surface of the tubes in the surface condenser. 
The vacuum is maintained in the condenser by the action 



192 PRACTICAL STATIONARY ENGINEERING 

of the air pump. A perfect vacuum cannot exist, and in 
the condenser there is always more or less pressure from im- 
perfect condensation and air passing in with the condensing 
water. 

To produce a vacuum in a surface condenser, open the 
injection valve shortly before starting the engine, so that 
the circulating water may enter the condenser tubes and 
cool them. Then, when the engine is started, the exhaust 
steam comes in contact with the cooling surface of the tubes, 
and is condensed, then a vacuum is formed. 

How is vacuum measured? 

The vacuum is measured by inches in the height of a col- 
umn of mercury, 2 inches of mercury equalling 1 pound 
pressure per square inch. Thus 10 inches of mercury 
means 10 pounds' pressure per square inch. The state of the 
vacuum is shown by the vacuum gauge attached to the con- 
denser; and, if it be imperfect, the cause must be ascer- 
tained and the fault corrected. If the water in the hot 
well is above the ordinary temperature, more injection w r ater 
must be admitted; and, if the vacuum continues imper- 
fect, the case may be due to an air leak, the location of which 
the engineer must endeavor to discover. Very often the 
fault will be found in the joint of the injection pipe, the 
gland of which will require to be tightened. The joints of 
the condenser may be tested by holding a candle to them, 
the flame of which will be drawn in if the joints are leaky. 

Is vacuum power? 

A vacuum is not power, as all power in the steam engine 
is derived from the pressure of steam on the piston. If 
there is no resistance on one side of the piston, the entire 
pressure on the other side is available. Whenever there is 
resistance on one side of the piston, it must be deducted 
from the pressure on the other side. 



CONDENSERS 193 

The temperature of the overflow from air pump to hot 
well should not be over 100° F. 
Water will be lifted 1 foot for each inch of vacuum. 



VACUUM GAUGE. 

How is vacuum recorded? 

The vacuum is recorded by a vacuum gauge connected 
with the condenser and piped to the engine-room. It reg- 
isters the vacuum in inches. Inches are used instead of 
pounds, because they correspond with the mercury column, 
the mercury column being always used to measure the press- 
ure of the atmosphere. A mercury column is frequently 
used in place of a vacuum gauge. With a perfect vacuum a 
column of mercury 30 inches high will be supported by the 
atmosphere. Vacuum gauges are usually graduated to agree 
with the scale of the barometer, and the vacuum is usually 
stated in inches of mercury. 

The absolute pressure of steam is measured from zero, and 
consists of the pressure indicated by the steam gauge (which 
is known as pressure above atmosphere). 



CHAPTER VIII. 

THE AMERICAN THOMPSON IMPROVED 
INDICATOR, 

Leading Pulley. 

The leading pulley consists of a wheel which leads the cord 
through the hole to the scored wheel, over which the cord 
can be run any possible angle to connect with the motion, 
wherever it may be. The pulley works in a sleeve which 
rotates in the stand according to adjustments required, and 
is held in its position and adjusted by a thumb-screw work- 



/'" 




Figure 54. 



ing in a groove on the sleeve, which acts as a binding screw. 
In this manner it is held in any desired position, and is free 
to revolve the moment the binding screw is loosened. 

By means of a set screw the stand which carries the wheel 
can be adjusted to run the cord to any possible angle within 
a range of 360 degrees. This improved swivel pulley does 



AMERICAN THOMPSON IMPROVED INDICATOR 



195 



away with carrying pulleys from the fact that, no matter at 
what the angle of deflection may be or what direction it 
may be necessary to take the cord, it works smoothly. 

The pulley face and face of the groove in the paper cylinder 
are always at the proper position, one with the other, to 
take the cord to the motion, wherever it may be. 

In high speed, short stroke, electric light engines, great 
range of adjustment is generally necessary, as considerable 



NlMri-iS) A 



© 




Figure 55. 



trouble is often experienced, on engines running 300 revolu- 
tions per minute, in arranging the cord so as to use inde- 
pendent arcs, making connections so no distortion of dia- 
grams shall be given. 

Piston. 

The stem of the piston is constructed throughout of steel, 
the head being of a special hard bronze composition. The 



196 PRACTICAL STATIONARY ENGINEERING 

upper part consists of a sleeve which acts as a guide in the 
cylinder cap. 

The piston is connected with the pencil lever by a connect- 
ing rod having a cross-head at the upper end acting as a 
yoke to connect to the pencil lever. This cross-head is held 
in place by a small hexagon lock-nut. The top of the con- 
necting rod being threaded permits of the raising and lower- 
ing of the cross-head and forms a means of adjusting the 
position of the atmospheric line on the diagram. 

The lower end of the connecting rod forms a socket which 
rests on the ball stud which is adjustable in the piston stem. 
This gives a perfect ball-and-socket joint, and provides means 
for taking up the lost motion. 

The piston is grooved for water packing, and is made as 
light as is consistent with the strength necessary to prevent 
expansion from pressure. 

Cylinder. 

The cylinder in which the piston travels is also made of 
a special hard bronze composition, which differs slightly 
from the piston head and produces a uniform expansion. 

The cylinder is held securely at one end, having sufficient 
space between the cylinder and outer casing to form a suitable 
steam jacket. 

Coupling. 

The connection to the indicator cock consists of a swivel 
coupling having a tail piece which is screwed into the lower 
end of the cylinder, provided with a shoulder against which 
the inner flange of the coupling proper rests, forming a per- 
fect swivel coupling, and is a decided improvement over 
the form of coupling having the right and left hand thread. 



american thompson improved indicator 197 

Springs. 

The springs are made of the finest quality of steel wire, 
and are wound on a mandrel and tempered in the most care- 
ful manner. 

All the springs are wound on mandrels from 4 to 4 J 
threads to the inch/ and thereby give more wire to each 




Figure 56. Figure 57. 

spring, and a consequent less strain than if wound, as in 
springs of other indicators, on mandrels two to three threads 
to the inch. 



198 PRACTICAL STATIONARY ENGINEERING 

All springs used in other instruments, whether double ; 
single, or having a steel bead for bottom end when con- 
nected, and under steam pressure, do not possess the free- 
dom of movement claimed, but are, in fact, as rigid as those 
made with double heads. 

All springs made by this manufacturer are scaled pro- 
viding for vacuum, and the capacity of any spring can 
be ascertained by the following general rule: Multiply 
scale of spring by 2J, and subtract 15, and the result will 
be the limit of pounds' steam pressure to which spring should 
be subjected. Example: 40-pound spring X 2 J = 100 — 15 
= 85 pounds' pressure, capacity of a 40-pound spring. 

To adapt the American Thompson Improved Indicator 
to all pressures, springs are made to any desired scale. The 
following are the most generally used: 6, 8, 10, 12, 16, 20, 
24, 30, 32, 40, 48, 50, 56, 60, 64, 70, 72, 80, 100, 120, 150, 
200. For pressures from 65 to 85 pounds a 40-pound spring 
is best adapted, for, as 40 pounds' pressure on a 40-pound 
spring will raise pencil 1 inch, 80 pounds' pressure on the 
same spring will raise pencil about two inches, which is the 
usual height of a diagram. 

Vacuum Springs. 

All springs are scaled providing for vacuum, but close 
experiments have shown that, from the fact that springs 
compress and elongate in unlike proportions, the regular 
pressure springs vary about 1 pound in 30, or about 3 J 
per cent. 

To Change Springs. 

First unscrew the milled nut at the top of steam cylinder. 
Then take out piston, with arm and connections. Discon- 
nect pencil lever and piston by unscrewing the small knurled- 



AMERICAN THOMPSON IMPROVED INDICATOR 



199 



headed screw which connects them. Remove the spring 
from the piston, substitute desired one, and put together 
in same manner, being careful, of course, to screw the spring 
up against shoulder, and down full to the piston head. This 
arrangement does not require the use of wrench or pin of 
any kind. 

To change springs in all other instruments, either a pin 
or wrench must be inserted between the coils of the spring, 
disconnecting the piston. By reason of the form of the 
coils not over one-sixteenth of an inch throw can be got by 
the pin or wrench at one time. When the piston is not, the 
trouble attending such an operation can be imagined. The 
length of the springs varies according to scale, and requires 
no adjustment of atmospheric line. Furthermore, in the 
American Thompson Improved Indicator the ball-and-socket 
joint is adjusted to scale with each spring a complete 
vacuum, or its equivalent, 14.7 pounds; and this adjustment 
need never be changed. But in other instruments, every 
time a spring is changed, this adjustment must necessarily 
be changed, and the readjustment, to show a vacuum with 
each spring, rests with the party using indicator. 

Maximum Safe Pressures to which Springs can be subjected 
when used with j square inch area plston. 



Scale of 


Pounds per 


Scale of 


Pounds per 


Spring. 


Square Inch. 


Spring. 


Square Inch. 


8 


6 


50 


110 


10 


10 


60 


135 


12 


14 


64 


145 


16 


23 


72 


160 


20 


33 


80 


175 


24 


45 


100 


215 


-30 


60 


120 


260 


32 


65 


150 


330 


40 


85 


200 


425 


48 


105 







All springs scaled for J square inch area piston. 
When J square inch area piston is used, the capacity of 
the spring is doubled. 



200 



PRACTICAL STATIONARY ENGINEERING 




Figure 58. 
With 1|-inch Paper Drum. 




Figure 59. 
Outside View 



AMERICAN THOMPSON IMPROVED INDICATOR 201 




Figure 61. 
The American Thompson Improved Indicator Complete with Fittings. 




Figure 62. Figure 63. 

The American Thompson Improved Indicator with New Improved 
Detent Motion (Patented). 



202 PRACTICAL STATIONARY ENGINEERING 

The above illustrations show a well-known American 
Thompson Improved Indicator fitted with a new improved 
detent motion. This device possesses many valuable qual- 
ities, especially when applied to high-speed stationary en- 
gines, locomotives, and marine engines. In taking indi- 
cator diagrams from high-speed engines, it is very difficult 
sometimes to take off one card and put on another for the 
reason that the movement of the drum carriage must be 
stopped while changing the card, or while the drum is re- 
moved and put on again. This stopping and starting of 
the drum carriage of the ordinary indicator, whenever it- 
becomes necessary to put on a new card, however accom- 
plished, is usually attended by many vexatious happenings 
and disagreeable results. This is wholly obviated by using 
the new improved detent motion, as the drum carriage, 
after it is once connected with the reducing motion, need 
not be disconnected until desired. In taking cards from 
locomotive and marine engines, it is usually much more 
difficult to connect and disconnect the drum carriage with 
the reducing motion than it is with the stationary engines. 
In taking cards from marine engines, it is often very desir- 
able or necessary, on account of close quarters and heat, 
to take the drum off the indicator in order to put on a new 
card, and this results in the spoiling of the fit of the drum 
of the ordinary indicator, and thereby causing it to run out 
of true, — a very objectionable feature, which the new detent 
motion entirely obviates, as the drum fit on the spindle is 
a long, lubricated bearing, well adapted for wear. 

The object of the reducing wheel is to reduce accurately 
the motion of "an engine cross-head to that required for a 
paper drum of an indicator, and to give the required length 
of diagram, regardless of the engine stroke. If either the 



AMERICAN THOMPSON IMPROVED INDICATOR 



203 



indicator or reducing motion is not correct, the cards are 
useless and deceptive. Hence the first step towards ob- 
taining the true state of affairs in a steam cylinder is an 
indicator that will show the pressure and a correct reduc- 
ing motion by which diagrams can be taken, so that an in- 




FlGURE 64. 

The American Thompson Improved Indicator with American Ideal 
Reducing Wheel. 



telligent engineer can interpret them, adjust the valves, 
and figure the power developed. 

This wheel is made of aluminum, brass, and steel, com- 
bining lightness and strength, — two essential features. The 
wheel drum from which the cord passes to the cross-head 



204 PRACTICAL STATIONARY ENGINEERING 

is only 2f inches in diameter, and is made of aluminum. 
The coil spring for the take-up is in a separate case, and con- 
nected by a three-to-one gear with the cord-wheel spindle, 
so that, while the light aluminum cord- wheel makes three 
revolutions, the spring makes but one. The spring can be 
adjusted to any desired tension to keep the cord taut on 
return stroke. The cord- wheel revolves on a steel screw. 




Figure 65. 

the thread of which is the same pitch as the cord, so that, 
when the cord is drawn out, the wheel travels as it revolves. 
By this means the cord is wound smoothly on the drum, 
and passes straight through the guide pulley. 

To use the reducing wheel on the indicator, remove the 
carrier pulley from the indicator and put the wheel on in 
place of it. Pass the drum cord around the small disk 
through the hole and under the holder, being careful to see 
that the cord is wound around the bushing or disk from the 
left, as shown in figure. Before attaching hook, see that cord 
on the wheel and indicator is taut at shortest part of the 
stroke, and that it will pull out a little farther than the 
longest part of the stroke. 

The reducing wheel can be used in any place where it is 
most convenient, bearing in mind that the cord from it 



AMEKICAN THOMPSON IMPROVED INDICATOR 205 

to the cross-head should run in a straight line. In un- 
hooking the cord, allow it to return slowly until the stop 
reaches the guide pulley. 

Bushings of various sizes are furnished for small disks, 
so that cards can be taken from any length of stroke up to 
72 inches. 

THE AMERICAN PANTOGRAPH. 




Figure 66. 

The above cut shows another form of reducing motion, 
known as the pantograph, or lazy tongs, especially adapted 
for slow-speed and long-stroke Corliss or slide-valve engines. 

Description. 

It consists of a lazy-tongs system of levers. The long 
levers are of cherry, 16 inches between centres, 1J by j$ in 
size. The hitch strip (G) is arranged so that it may be 
shifted in the holes (E), which brings a hitch pole (F) in a 
line passing through pivots (C, D). 

There must be a vertical hole in the engine cross-head so 
that pivot (C) can be dropped into it. 



206 PRACTICAL STATIONARY ENGINEERING 

A post must be set in the floor near the guides, with a 
socket in the top for pivot (D). 

The stake socket must be level with and directly opposite 
the cross-head socket when the latter is at mid-stroke. 

The indicator cord is hooked to the centre peg (F), and the 
stake should set at such a distance from the guides that the 
cord will lead off parallel with the guides. Otherwise, a guide 
pulley will be necessary. 

When the pantograph is in motion, every point on a line 
cutting C-D has a true motion parallel with the guide, vary- 
ing in distance from nothing at D to length of stroke at C. 

It is only necessary to hitch the cord at a point on this line 
to give the right amount of motion to the cord. This point 
will be near (D) and within the range of adjustment of the 
strip G. 



THE AMERICAN AMSLER'S POLAR PLANIMETER. 

There are several other instruments which are used as 
accessories to the indicator, and which greatly facilitate the 
using of the instrument, one of which is Amsler's Polar 
Planimeter, as shown by the accompanying cut, for measur- 
ing the area of indicator diagrams. By using this instru- 
ment, the whole work of measuring a diagram can be done 
in one minute. 

Engineers who have many indicator cards to work up can- 
not afford to be without a planimeter. 

Directions for Using the Planimeter. 
Press the point A slightly into the paper, not clear 
through, in such position that the tracer B will follow the 
desired line without bringing the roller C against any pro- 



AMERICAN THOMPSON IMPROVED INDICATOR 207 




Figure 67. 



208 PRACTICAL STATIONARY ENGINEERING 

jection. The roller must move on a continuous flat 
surface. 

It is also well to fasten the diagram to a drawing board, or 
some other flat surface, by means of pins or springs, to pre- 
vent it from slipping. 

Mark a starting point at any point on the outline of dia- 
gram D, set the tracer on that point, and place zero on the 
roller so it exactly coincides with the zero on vernier E. 

Now trace the line, moving in the direction travelled by 
the hands of a watch : stop at the starting point and take the 
reading. 



f 

| I IH| I I I| | I I l ' l I ' l V l 'l'l 1 ! 1 ! 1 ! 1 !' ! |'1HI|I III |HH | I 



Figure 68. 

First. Find the highest figure on the roller that has passed 
the zero on the vernier, moving to the left, which we will 
assume to be 4. Now the construction of instrument is such 
that each figure on the roller represents an equal number of 
square inches. 

Second. Find the number of completed divisions between 
4 on the roller and zero on the vernier, which we will assume 
to be 5. 

Third. Find the number of the mark on the vernier 
which coincides with some mark on the roller, which in this 
case may be 6. 

We now have the exact reading, 4.56, or 4 -f^ inches area. 

In measuring diagrams of more than ten inches area, add 
10 to the result. 

To those who are perfectly familiar with the instrument, 



AMERICAN THOMPSON IMPROVED INDICATOR 209 

it is not necessary to place the zeros so they coincide, but 
take the reading as it is, and subtract it from the result. 
Should the second reading be less than the first, add 10 to 
the second reading before making the subtraction. 

For instance, should the first reading be 8.42 and the 
second reading 2.68, add 10 to the second reading, thus: 
2.68+10 = 12.68 — 8.42=4.26 square inches. 

If the area to be measured be very large, divide it by lines 
into areas of less than twenty square inches and take sepa- 
rate measurements. 

If the drawing be to a scale, multiply the result by the 
square of the ratio number of the scale. 

Should we desire to find the area of a plan containing 5 
square inches, drawn to a scale of 100 rods to the inch, we 
square the ratio number and multiply by 5, thus : 100 X 100 
= 10,000 X 5 = 50,000 square rods. 

In using the planimeter for indicator diagrams, for which 
it is specially adapted, we find the area of the diagram ac- 
cording to the foregoing directions, which we will assume to 
be 2.48. We now measure the length of the diagram parallel 
with the atmospheric line, which we will say in this case is 
4 inches. 

Now divide the area by the length. The quotient is the 
mean or average height of the diagram in inches, which is 
.62 inch. This we multiply by the scale of the indicator, 
which we will assume to be 40. The product gives us 24.8 
pounds, mean pressure each square inch of the piston. 

Expressed arithmetically, 2.48 -f 4 = .62 X 40 = 24.8. 

It can also be used for measuring any regular or irregular 
plot or diagram. 



210 PRACTICAL STATIONARY ENGINEERING 



INDICATORS, 

What do the numbers stamped on an indicator spring sig- 
nify? 

The pressure necessary to raise the pencil 1 inch. A No. 40 
spring makes a card 1 inch high for each 40 pounds of steam 
pressure at the engine. 

How do you select the proper spring to use in indicator? 

Divide the gauge pressure by 2. 

What is the usual size of card? 

4 inches long, 2 inches high. 

How do you find what steam pressure a spring is good for? 

Rule. — Multiply scale of spring (or number stamped upon 
it) by 2 J. From this product subtract 15 (never exceed this 
rule). 

Example. — What spring should be used for an engine run- 
ing under 100 pounds' boiler pressure? 

100 -5-2=50= spring for a card 2 inches high. 

What is the maximum pressure you would allow a No. 50 
spring to work under? 

50 X 2J = 125 — 15 = 110 pounds. 

What are indicator cards? 

It is a diagram showing at any part of the stroke the press- 
ure acting upon the piston. 

Before taking a card, what must be done? 

Cylinder drips must be opened to free the cylinder of water. 
This precaution is taken so as not to injure the indicator. 

What record is taken when taking a card? 

Cylinder diameter, stroke, name and end of cylinder (as 
high pressure, left hand), number of spring, revolutions per 
minute, gauge pressure, and reading from vacuum gauge, if 
on a condensing engine. 



AMERICAN THOMPSON IMPROVED INDICATOR 211 

What is taken first, atmospheric line or diagram, and why ? 

Steam is allowed to enter the cylinder of the instrument to 
warm it up before any cards are taken. The atmospheric line 
is taken after the cards are taken, as greater accuracy is ob- 
tained when all lines are taken near the same temperature. 

How do you get an atmospheric line on card, and why 
used? 

By swinging the pencil against the paper on drum while 
there is no steam in the indicator. It is used as a reference 
line for back pressure. 

Where is the atmospheric line in a non-condensing engine 
in regard to card? 

It is below the diagram, the distance corresponding to the 
back pressure. 

Where is the atmospheric line in a condensing engine in 
regard to card? 

It passes through the diagram near the lower edge. The 
distance between the lines represents the vacuum. 

Why is the boiler pressure line drawn on the diagram? 

To observe the drop in pressure between the boiler and 
cylinder. 

How do you locate the clearance line in a diagram? 

Rule. — Multiply total length of card by percentage of 
clearance, and set off this distance from end of diagram, 
drawing the clearance line at right angles to vacuum and at- 
mospheric lines. 

What may be learned by the indicator diagram? 

It is used to determine not only the horse power and water 
consumption, but also shows the condition of valves, whether 
they are leaky or properly set, or leaky piston, etc. 

What does the length of a card represent? 

It is proportional to and represents the stroke of the engine. 



212 PRACTICAL STATIONARY ENGINEERING 

What does the height represent? 

It is proportional to and represents the boiler pressure. 

What is meant by a full-load card? 

A full-load card is taken when the engine is carrying all the 
load. 

What is meant by a friction card? 

A friction card is taken while the engine is running up to 
speed, and the load thrown off. 

What does this show particularly, and why used? 

It shows the amount of friction in reciprocating parts, and 
is used in calculating the efficiency of the engine. 

What is the mean effective pressure? 

Mean effective pressure is the average pressure which would 
have to act upon the piston throughout the entire stroke 
to cause the engine to develop the same power as under the 
indicated conditions, and is abbreviated M. E. P. 

How is the mean effective pressure found from the card? 

Rule. — Multiply area card by the spring used, and divide 
this product by length of card. 

Example. — The card taken from one end of a cylinder is 
found to contain 2 square inches. A 60 spring was used. 
Length of card was 3J inches. What is the mean effective 
pressure ? 

2 X 60 = 120 -*- 3i = 34.3 M. E. P. 

How may the mean effective pressure be found? 

By use of ordinates or on equally spaced lines, and by use 
of the planimeter. 

Explain the method of using ordinates. 

The length of card is divided into 10 equal spaces. The 
distance from the lower line to the upper line of card is 
measured through the middle of these spaces. The length of 
these lines are added (in inches) and multiplied by scale of 



AMERICAN THOMPSON IMPROVED INDICATOR 



213 





















'IT™ 

! i 

t 

ll 
1 1 
H 
1 1 

V 


1 

1 


1 

1 
1 
1 
I 
1 

1 


i 
i 
i 
i 
I 
i 
1 




i 
i 


PI 




N 


v*L 


1 
! 


i 
i 




I 
i 

i 


1 
1 


i 

i 

i 


1 1 









































H 


S- 




1 1 
• i 

!i 






i 
i 

i 
i 


=._ ^ 


v^- 




t 1 
| 1 
|-| 


^i^_ 




i 

1 

i 

i 

i 
i 


1 * 


Vfc 




1 
1 
1 


1 
1 


1 1 

1 L 























Figure ( 



214 PRACTICAL STATIONARY ENGINEERING 

spring used. This product is then divided by 10, or the 
number of spaces used, which gives the mean effective press- 
ure. 

Which is the more accurate? 

The planimeter, as areas can, by careful work, be measured 
to T £o of a square inch. 

Where a loop appears on a diagram, and you are using 
ordinates, what must you look out for? 

That the area of the loop is subtracted from the whole 
area. Using the planimeter, the instrument takes care of it 
by performing the subtraction automatically. 

What is clearance? 

It is the volume expressed in percentage of whole cylinder 
volume of the space between the face of piston, inner face 
of cylinder head, and volume of port to edge of valve seat. 

How is the volume found? 

Place engine at extreme stroke, and through indicator 
connection or any opening in top of cylinder pour in through 
a tunnel water which has been carefully weighed. Divide 
this weight of water by 62.5 (which is the weight of a cubic 
foot of water), which will give the number of cubic inches. 
Multiply area of cylinder by stroke in inches, which will give 
total volume of piston displacement. Divide the number of 
-cubic inches of clearance by the piston displacement, the 
quotient will then be percentage of clearance. 



AMERICAN THOMPSON IMPROVED INDICATOR 215 

Example. — What is the percentage of clearance in an en- 
gine cylinder 20 inches diameter by 36 inches stroke, weight 
of water to fill clearance space is 30 pounds? 

62.5)30.000 (.48 = cubic feet volume of clearance. 
2500 



5000 
5000 



314.16= area 20-inch cylinder. 
36= stroke in inches. 



188496 
94248 



11309.76 = cubic inches of piston displacement. 

1728)11309.76(6.54 = cubic feet displacement of piston. 
10368 



9417 
8640 



7776 
6912 

6.54).4800 (.0733 = 7.3 per cent, clearance. 

4578 



2220 
1962 
2580 
1962 



What is a theoretical card? 

A diagram showing perfect action of valves, expansion of 
steam, etc. 



216 PRACTICAL STATIONARY ENGINEERING 

How is the piston speed in feet per minute found? 

Rule. — Multiply stroke in inches by the number of strokes 
per minute and divide by 12. Number of strokes equal 
revolutions per minute; multiply by 2. 

For accurate calculations for high pressure, what is done 
with the piston rod area? 

If rod passes through one head, one-half area of rod is 
deducted from piston area; if rod passes through both heads, 
whole area of rod is deducted from area of piston. 

What are the four periods of distribution of steam in an 
engine ? 

Admission, expansion, exhaust, and compression. 

What is the most probable cause of a wavy expansion line ? 

May be vibration of the spring, or perhaps indicator piston 
sticks, or water in cylinder of engine. 

What do sharp corners or changes in direction on a dia- 
gram signify? 

Quick opening of valves. 

What do round corners signify? 

Slow opening of valves with wire drawing. 

What is meant by wire drawing? 

By wire drawing is meant throttling; caused by choked 
passages, ports too small, steam pipe too small, etc. 

What is initial pressure? 

It is pressure in the cylinder at the beginning of the stroke. 

What is terminal pressure? 

It is the pressure in the cylinder at the end of the stroke. 

What is back pressure? 

It is the pressure above atmosphere the steam on the live 
end has to counteract on the exhausting end in doing its 
work. 



AMERICAN THOMPSON IMPROVED INDICATOR 217 

Are cards ever taken from anything but a steam engine ? 

Sometimes from the main steam pipe or receiver, condenser, 
or on a non-condensing engine from the exhaust pipe. 

What is shown on the cards, when taken from the main 
steam pipe? 

Whether or not steam has a free passage to the engine. 

What is shown on the cards taken from the receiver? 

The variation of steam pressure. 

What is shown on the cards taken from the exhaust pipe 
or condenser? 

Whether or not the exhaust steam has free passage from 
the cylinder. 

Are cards ever taken from a steam pump? 

Quite frequently cards are taken from the steam and water 
end of a steam pump. They show how accurately the valves 
work, and also the tightness of piston-rod stuffing boxes, and 
by comparison of both ends the amount of friction can be 
ascertained. 

In attaching an indicator to water end, what precaution 
must be observed? 

To place the indicator cylinder horizontally, to avoid air 
collecting in cylinder and acting as a cushion, which would 
not give accurate results. 

What do you understand by atmospheric pressure? 

It is the weight of air (expressed in pounds per square 
inch) surrounding the earth, and equals 14.7 pounds. 

What is vacuum? 

It is the absence of pressure. 

What is gauge pressure? 

Gauge pressure is the boiler pressure, as indicated by the 
steam gauge, or the pressure per square inch in the boiler. 



218 PRACTICAL STATIONARY ENGINEERING 

Does the pressure affect the evaporation? 

Yes, the lower the pressure, the lower the temperature nec- 
essary to boil water. 

Does the temperature of steam affect the pressure? 

An increased temperature raises the pressure. 

What is wet saturated steam? 

It is steam containing a percentage of moisture. 

What is superheated steam? 

It is steam having a temperature higher than that due to 
pressure. 

Explain what is meant by ratio of expansion. 

It is the number of times the volume of steam in the cyl- 
inder up to point of cut-off is expanded. 

What is the average back pressure on a non-condensing engine ? 

Usually on an economical engine this, is about 17 pounds 
absolute. 

What is the average back pressure on a condensing engine ? 

Usually about 3 pounds absolute. 

What is meant by the efficiency of an engine ? 

It is a comparison of the amount of feed water with the 
amount of steam taken from the diagram. 

Explain what you understand a partial vacuum to be. ' 

If air in a sealed vessel were pumped out, so that the gauge 
should read less than atmospheric pressure, a perfect vacuum 
would be contained in the vessel. 

At what temperature will water evaporate? 

Under atmospheric pressure of 14.7 pounds, water will 
evaporate at 212° F. 

A cubic foot of water will make how many cubic feet of 
steam at atmospheric pressure? 

It will make 1,646 cubic feet. 

What occurs when steam is cooled? 

It will condense into water. 



AMEEICAN THOMPSON IMPROVED INDICATOR 



219 



DEFECTIVE DIAGRAMS. 

An expansion curve that is higher than it should be may arise 
from a leaky valve, letting in steam after the cut-off takes place. 




**se 



A ? £ / O/?£'$£/VT0T/Oa/ Of / /a/£S OsS /9 C*£>Z> 




l£#tcy P/sto*/ 




A//*e 27&0M/fl/ 




TOO /1</Ct/ £-£#37 

. Figure 70. 



220 



PRACTICAL STATIONARY ENGINEERING 



An expansion curve that is lower than it should be may 
be caused by a leaky piston or it might be caused by a leaky 
valve. 




l#T£ tfjj/y/ss/o*/ 




Too tfvc/f Ce/*7 / /e*£-SS/<?"' 




Figure 71. 



AMERICAN THOMPSON IMPROVED INDICATOR 



221 



Suppose you had a leaky valve and a leaky piston. 
In that case, as a result the expansion curve may appear 
correct and not show the leak. 




fvexywsq Too />*// 
&£f7£27y J7£CX£-4S£ f«fl£ 




tfXrf/sS/CA/ Too l*T£ 
°f~ #*>^**C£L 



Figure 72. 
Remedy is to set the eccentric back. 




Figure 73. 



222 



PRACTICAL STATIONARY ENGINEERING 




sfreeiM lap Too J V7/9 / / 




/MJ/C *TOf? /*£■* T/ *f 




STIC /C/As/q o/r /a/J3/c#TO& PiSTOrJ 

Figure 74. 



AMERICAN THOMPSON IMPROVED INDICATOR 223 




£ccfnt#,c SL, r/S£ x £*?/<: 




Bffak- F/fe-ss Too ///<$// 




Figure 75. 



224- PRACTICAL STATIONARY ENGINEERING 

How would you know if the valve did not have proper 
lead? 

Lead would be shown by the piston moving a certain 
portion of the stroke before the steam line attained its great- 
est height. The upwards line from the admission line is 
at right angles instead of rising vertically, showing that the 
piston had moved a certain portion of its stroke before full 
pressure of steam was admitted. 




J?o</3L£ /tp/j/ss/oa/ 




£CC BNT-R-I.Q Too fRR rftfEBT 
Figure 76. 



AMERICAN THOMPSON IMPROVED INDICATOR 



225 



Excessive lead is shown by the lap where compression 
curve extends up to the steam line. The lead carries the 
admission line above it on account of piston moving against 
the incoming steam. 




Figure 77. 



How is a theoretical expansion curve on card constructed? 

On the diagram lay off the line CD from the atmospheric 
line equal to 14.7 pounds (using same scale as spring in in- 
strument when card was taken). 

From the admission line draw BC, this distance represent- 
ing the clearance (as found by preceding rule). 

Draw BA parallel to CD, representing boiler pressure, 
plus 14.7 pounds, measured from CD. 

Select any point, g on expansion line, and draw gG per- 
pendicular to CD and intersecting BA. Draw CG. At 
g draw a line parallel to CD and intersecting CG. From 



226 PRACTICAL STATIONARY ENGINEERING 

this point of intersection draw a line perpendicular to CD 
.and intersecting BA at point c. This point is the theoretical 
point of cut-off. Select any point, E, on BA. Draw CE. 
Draw Ee perpendicular to CD. Where CE intersects Cb, 
draw a line parallel to CD to reach Ee. This is one point 
of the theoretical expansion curve. 

Select any point, F, H, A, card. Draw in similar manner 
through these points thus found a curved line, which is the 
theoretical curve of expansion. 

How do you figure the distance from end of diagram to 
clearance line? 

• Rule. — Multiply the length of card by the percentage of 
clearance. 

Example. — What is the distance from clearance line to end 
of diagram on an engine having 6 per cent, clearance and 
length of diagram equals 3 inches? 

6% = .06 X 3 = .18 inch. 

If actual clearance is not known, how may it be found 
approximately by the theoretical expansion curve? 

Select two points on the expansion line, C (card), g. Draw 
Gg and cb perpendicular to CD. From g draw a line par- 
allel to CD and intersecting cb. From this intersection 
draw to G, extending line to cut CD, or at point C. Draw 
BC at the intersection, which is the clearance line. 



AMERICAN THOMPSON IMPROVED INDICATOR 227 



HORSE POWER. 

Rule. — To figure the horse power of an engine, certain data 
must be known, first, the mean effective pressure; second, 
the length of stroke in feet; third, the area of cylinder in 
square inches; and, fourth, the number of strokes per minute. 
The mean effective pressure is found directly from the cards 
taken (see rule). The length of stroke in feet is also found 
by rule previously given. The area of cylinder is found by 
multiplying the square of the diameter by .7854, and the 
number of strokes is found by multiplying the number of 
revolutions per minute by 2. 



RULE FOR HORSE POWER. 

Horse power (or 33,000 the constant) is an expression for 
work in foot pounds, and means the amount of power neces- 
sary to raise 33,000 pounds 1 foot in one minute. 

Rule.— Multiply the M. E. P. by length of stroke in feet 
by the area of cylinder in square inches and by the number 
of strokes per minute. Divide this product by 33,000. The 
■ result is the indicated horse power of the engine. 

By deducting the friction H. P. from the indicated H. P., 
the remainder will give the actual H. P. 

Example. — A set of cards taken from a 12 x 36-inch 
engine gives as areas 4.1 and 4.0 square inches and is 3 J 
inches long. A 40 spring was used, the engine running 112 
revolutions per minute. 



228 PRACTICAL STATIONARY ENGINEERING 

4.1 

4.0= area of cards. 

2Js7i 

4.05 = average area. 
40 = spring. 



length of card =3.5)162.00(46.28 =M. E. P. 
140 
220 
210 



100 46.28=M. E. P. 

70 3= length of stroke in ft. 

12 "300 138.84 

12 280 113.09= area of cylinder. 

144 124956 

.7854 41652 

144 13884 



31416 13884 



31416 15701.4156 

7854 224 = strokes per minute. 



113.0976 628056624 

314028312 
314028312 



33000)3517117.0944(106.57 = horse power. 
33000 



112=revs. 217117 

2 198000 



224= strokes. 191170 

165000 



261700 
231000 



AMERICAN THOMPSON IMPROVED INDICATOR 229 




/?/<zyr //*/>/27 C/l/*2£* 




^£fr fa#j C/l//vze* 




£*/ r fa»/j Cyt/A/jrr* 




Figure 78. 



230 PRACTICAL STATIONARY ENGINEERING 

These cards were taken from a 9 X 5| double upright 
Sturtevant engine, boiler pressure 84 pounds, spring 60, 
revolutions full load 348, revolutions friction 350. Figure 
horse power for friction and full load efficiency. 



R. H. cylinder. 



Full-load Cards. 

2.00 = area head end. 
1.98 = area crank end. 



2)3.98 



1.99=average area. 
60 = spring. 



length of card=2.8)119.40(42.642=M. E. P. 
112 
74 
56 
180 
168 
~120 
112 



80 
56 



5J inches = 5.5 = length of stroke. 

12)5.5(.458, call this .46 (of a foot). 
48 
~70 
60 
100 
96 



AMERICAN THOMPSON IMPROVED INDICATOR 231 

348 = revolutions. 

2 
696 = strokes per minute. 

42.64 = M. E. P. 
.46 = stroke in feet. 



25584 
17056 



19.6144 
63.62= area 9-inch cylinder. 



392288 
1176864 

588432 
1176864 



1247.868128 

696= strokes per minute. 



7487208 
11230812 

7487208 



33,000)868516.128(26.31 =H. P. of R. H. cylinder. 
66000 
208516 
198000 



105161 
99000 



61612 
33000 



232 PRACTICAL STATIONARY ENGINEERING 

L. H. cylinder. 2.00 = area head end. 

2.00= area crank end. 
2)400 

2.00 = average area. 
60 = spring, 
length of card = 2.8)120.00(42.8=M. E. P. 
112 



80 42.8 = M. E. P. 

56 .46 = stroke in feet. 



240 2568 

224 1712 



19.688 
63.62= area cylinder. 



39376 
118128 
59064 
118128 



1252.55056 

696 = strokes per minute. 



751530 
1127295 
751530 



33,000)871774.80(26.41 =H. P. of L. H. 
66000 cylinder. 

211774 
198000 



26.31 =R.H. 137740 

26.41 = L.H. 132000 



52 .72 = total horse power 57400 
developed. 33000 



AMERICAN THOMPSON IMPROVED INDICATOR 233 



R. H. cylinder. 



Friction Cards. 

.40 = area head end. 
.15= area crank end. 
2JIE 
.275 = average area. 
60 = spring, 
length of eard=2.8)16.500(5.89 = M. E. P. 
140 
"250 
224 



260 
252 



5.89 = M. E. P. 

.46= stroke in feet. 



3534 
2356 



2.7094 
63.62= area cylinder. 



540 
1620 
810 
1620 



171.7740 

696= strokes per minute. 



103062 
154593 
103062 
119551.92 



234 PRACTICAL STATIONARY ENGINEERING 



1,000)119551.92(3.62 =H. 
99000 

205519 L. H. 
198000 
75190 


P. friction for R. H. cylinder. 

cylinder. 

.38 = area head end. 
.22 = area crank end. 


66000 






2).60 










.30= average area. 
60 




length of card =2.8)18.00(6.4 = 
168 
"120 
112 

6.4 = M. E. P. 

.46 = stroke in feet. 


=M. E. P. 




384 
256 










2.944 
63.62 = 


= area of cylinder. 






5888 
17664 
8832 
17664 










187.29728 

696= strokes per 


minute. 





1123782 
1685673 
1123782 



33,000)130358.712(3.95 = H. P. friction for L. H. cyl- 
99000 inder. 

313587 
297000 



165870 
165000 



AMERICAN THOMPSON IMPROVED INDICATOR 235 

3.62 = H. P. R.H. cylinder. 
3 : 95=H. P. L. H. cylinder. 
7.57=Total friction H. P. 

friction 100 X 7.57 = 757.00 

total H. P. developed =52.72)757.00 (14.3 = per cent, of fric- 

5272 tion. 







22980 






21088 






18920 






15816 






3104 


100 






14.3 






85.7 


per 


cent. 



efficiency = 



total horse power developed =52.72 
total friction H. P. = 7.57 
percentage of friction = 14.3 per cent, 
efficiency = 85.7 per cent. 

How do you find the quantity of steam used by an engine 
per minute? 

Rule. — Multiply area of cylinder in square inches by the 
piston speed in inches per minute and by the numerator of the 
fraction of cut-off. Divide this product by 1,728 times the 
denominator of the fraction of cut-off. Multiply this quo- 
tient by 60 for quantity of steam used per hour. 

Example. — Find the quantity of steam used per hour by 
a 10 X 20 engine running 80 revolutions per minute and 
cutting off at -J stroke. 



236 PKACTICAL STATIONARY ENGINEERING 

10= diameter cylinder. 
10 

100 

.7854 



78.5400= area of cylinder. 
20 = stroke. 



1570.80 

160 = number of strokes. 



942480 
157080 



251328.00 

1= numerator of J cut-off. 



251328 



1728 = cubic inches per cubic foot. 
3 = denominator of J' cut-off. 



5184 



5184)251328(48.48= cubic feet per minute. 
20736 
43968 
41472 



24960 
20736 
42240 
41472 

48.48 
60 



2908.80= cubic feet per hour. 



AMERICAN THOMPSON IMPROVED INDICATOR 237 

Why do you wish to know the amount of water used? 

The amount of feed water shows the total quantity furnished 
the boiler, and the indicator cards show actual amount used 
by the engine. The difference of these two amounts is the 
quantity used by leaky stuffing boxes, leakage in valve and 
piston, joints, etc. 

How do you find the quantity of water evaporated into 
steam per hour? 

Rule. — Multiply area of cylinder in square inches by the 
speed of the piston in inches per minute, and the numerator 
of the fraction of cut-off times 60, divide this product by 
1,728 times the volume of steam (at given pressure) times 
the denominator of the fraction of cut-off. 

Example. — Find the quantity of water evaporated into 
steam per hour to supply a 26 X 30 engine running 80 rev- 
olutions per minute, under 90 pounds per square inch 
boiler pressure, cutting off i 5 2 stroke. 

26= diameter of cylinder. 
26 
156 .7854 

52 676 

676 47124 

54978 
47124 



530.9304 = area of cylinder. 



238 PRACTICAL STATIONARY ENGINEERING 

530.93 

30= stroke in inches. 



15927.90 

160 = strokes per minute (80 revolutions X2). 
9556740 
1592790 



2548464.00 

60 = minutes per hour. 



152907840 

5= numerator of fraction j%. 
764539200 

1728= cubic inches 1 cubic foot. 
258.9= relative volume of steam at 90 pounds' 



15552 pressure (see steam table). 
13824 
8640 
4356 



537379.2 



10747584 

5373792 

6448550.4 



12= denominator of fraction fy. 



6448550)764539200.0(103.05 =lbs. of steam used 
6448550 per hour. 

19684200 
19345650 



33855000 

32242750 

1612250 



CHAPTER IX. 
HYDRAULIC ELEVATOR. 

Explain a hydraulic elevator. 

Hydraulic elevators consist of a piston rod and cross-head 
which carries a set of travelling sheaves and a>set of fixed 
sheaves. Now, when water is applied to the piston, it would 
pull these sheaves apart, causing the end of the cable in the 
hatchway to rise with the cage attached, at a speed much 
faster than that at which the piston travelled. The speed 
of cage would travel eight times as fast as the piston, or eight 
times as far. With this arrangement, when connected to the 
city mains, the water after being used was wasted. 

A great advantage was gained by the introduction of what 
was called the pressure tank, water being pumped into this 
tank, with inlet and outlet pipes taken from the bottom of 
the tank to prevent the escape of any of the air. There is also 
a glass to show the height of the water in the tank and press- 
ure gauge. Air would be pumped into the tank, one-third air 
and two-thirds water. There are two tanks needed, a pressure 
tank and an overflow tank. After the water is used in the 
elevator machine, it goes into an overflow tank, and is then 
pumped again into the pressure tank. The pipes connected 
to it are the pipe to the elevator machine, a discharge pipe 
from the pump, a pipe from the elevator machine to the over- 
flow tank, a pipe to the automatic governor on steam pipe to 
pump. The pump is operated automatically by a diaphragm 
valve in the steam pipe. To get air into the pressure tank, 
open the check- valve which is attached to pump above the 



240 PRACTICAL STATIONARY ENGINEERING 

suction valve and below the discharge valve, or open suction 
pipe from the overflow tank to pump. Water and air will 
then be pumped into the pressure tank. If you do not wish 
for the water line to rise, open overflow from pressure tank 
into overflow tank. 

Elevator machines are single acting. The weight of the 
car and people brings it down. This system would not 
work if the pressure tank was full of water. 

What is a hydraulic plunger elevator? 

A hoisting machine consists of a cylinder equal in length 
to the rise of the car and erected vertically beneath it. The 
cylinder is fitted with a plunger, to the upper end of which 
the car is fastened. 

The plunger is made of finished wrought or cast iron 
pipe. The water is admitted at the top of this cylinder 
through an improved, balanced double valve, with a water 
space of one inch between the plunger and cylinder and 
pressing upon the bottom of plunger. The weight of the car 
is counterbalanced. The plunger elevators take the least 
power to operate them. 



CHAPTER X. 
USEFUL INFORMATION, 

j^ = cube root, or that the number contained beneath it 
must have the cube root extracted; as, 1^343 = 7 

Pounds = cubic feet X 62.425 

Gallons = cubic feet X 7.48 

Pressure of water = height in feet X .4335 

Height in feet = pressure X 2.309 

Tons = cubic feet -f- 35.88 

Tons = gallons 268.36 

1 cubic foot = 62.425 pounds. 

1 cubic foot = 7.48 gallons. 

1 cubic foot =1728 cubic inches. 

1 cubic inch of water =.036 pound. 

27.71 cubic inches water weighs 1 pound. 

1 gallon = 231 cubic inches. 

1 gallon = .833 imperial gallon. 

1 gallon weighs 8.33 pounds. 

1 ton (long) =2,240 pounds. 

1 ton (short) = 2,000 pounds. 

1 ton = 35.88 cubic feet. 

1 ton = 268.36 gallons. 

About 125 gallons of petroleum oil is equal to a ton of good 
coal in making steam. 

26.37 cubic feet of steam weighs 1 pound: at atmospheric 
pressure 13.81 cubic feet of air weighs 1 pound, — so that steam 



242 PRACTICAL STATIONARY ENGINEERING 

exhausting into the atmosphere is equal in weight to prac- 
tically one-half that of the air. 

Doubling the diameter of a pipe or a cylinder increases the 
area and contents 4 times. 



Cubic 
Cubic 
Cubic 



inches of cast iron X .26 = weight in pounds. . 
inches wrought iron X .28 = weight in pounds, 
nch steel X .28 = weight in pounds. 



Cubic inches copper X .32 = weight in pounds. 
Cubic inches brass X .30 = weight in pounds. 
Cubic inches X .41 = weight in pounds. 
Cubic inches X .0036 = gallons. 

Cubic feet of coal X .0345 = tons in weight. 

The square of the circumference of a rope in inches X 
.66 = safe load in tons. 

The square of the diameter of a round bar of iron in inches 
X 2.64 = weight in pounds per foot. 

The square of the side of a square bar of iron in inches 
X 3.36 = weight in pounds per foot. 

Weight of 1 gallon of water = 8.35 pounds. 

1 cubic inch of air=.31 grain's weight. 

1 cubic inch of mercury = .49 pound's weight. 

A column of water 1 inch square, 1. foot high, weighs .433 
pounds. 

A column of water 27.71 inches in height exerts 1 pound 
pressure per square inch. 



USEFUL INFORMATION 243 

To reduce decimals of a foot to inches. 
Example. — Reduce .55 of a foot to inches. 

.55 X 12 = 6.60 = 6.6 inches. 

To reduce inches to a decimal part of a foot. 
6.6 -f- 12 = .55 of a foot. 

To find the number of feet of belting in a roll. 

Add the diameter of hole to the outside diameter of the roll, 
multiply this sum by the number of turns in the roll, and mul- 
tiply this product by .1309. 

To find the size and speed of pulleys. 

Rule. — Multiply the diameter of driver by the number of 
revolutions of driver, and divide this product by diameter of 
driven. 

Example. — A 30-inch diameter pulley, making 180 revo- 
lutions per minute, drives a counter-shaft with a 12-inch 
pulley. What is the speed of the counter-shaft? 

180 
30 



12)5400(450= revolutions of counter-shaft. 

48 
60 
60 

Example. — A pulley 30 inches diameter on a main shaft 
running 180 revolutions per minute is required to drive a 
counter-shaft 450 revolutions per minute. What will be the 
diameter of pulley? 

Rule. — Multiply the diameter of driver by the number of 
revolutions of the driver, and divide the product by revolu- 
tions of driven. 



244 PRACTICAL STATIONARY ENGINEERING 

180 
30 



450)5400(12 = diameter in inches of pulley on 
450 counter-shaft. 

~900 
900 

Example. — A counter-shaft with a 12-inch pulley is required 
to run 450 revolutions per minute. The revolutions of main shaft 
is 180. What size pulley must be used on the main shaft ? 

Rule. — Multiply diameter of driven pulley by the number 
of revolutions of driven, and divide this product by the num- 
ber of revolutions of driver. 

450 
12 



900 
450 



180)5400(30 = diameter of pulley in inches on main 
540 shaft. 

Rules. 

How many cubic inches are contained in a gallon? 

231 cubic inches. 

How many cubic inches are contained in a cubic foot? 

1,728 cubic inches. 

How many pounds are there in one gallon of water? 

8.34 pounds. 

What is the weight of a column of water 1 inch square and 
1 foot high? 

.432 pound. 

How do you find the number of cubic inches per stroke? 

Square the diameter, multiply this product by the stroke 
in inches, and multiply this last product by .7854. 



USEFUL INFORMATION 245 

How do you find the number of gallons per stroke? 

Square the diameter, multiply this product by the length 
of stroke in inches, and multiply this last product by .7854. 
Divide this value by 231. 

How do you find the number of gallons per minute? 

Multiply the square of the diameter by the stroke in inches 
per minute, by the number of strokes per minute, and by 
.7854. Divide the product by 231. 

Example. — A pump having a 10-inch cylinder and 12- 
inch stroke makes 40 strokes per minute. If the pump is 
double-acting, how many gallons will it pump per minute? 

10 = inches diameter cylinder. 
10 = inches diameter cylinder. 
100 = square of cylinder. 
.7854= const ant. 
78.54 

12= stroke in inches. 



15708 

7854 



942.48 [double acting). 

i No. cu. in. 80 = number of strokes X 2 (for 

1 in 1 gal. =231)75398.40(326.4 =gallons per minute. 
693 
609 
462 
1478 
1386 
924 
924 



246 PRACTICAL STATIONARY ENGINEERING 

How do you find the horse power necessary to lift a given 
quantity of water a given height ? 

Multiply the quantity in gallons by the height in feet, and 
this product multiply by 8.34. Divide this last product by 
33,000. 

Example. — From a tank containing water we wish to raise 
100 gallons per minute to a height of 10 feet. What horse 
power is necessary, friction not considered? 

100 = gallons to be raised. 
_12 = feet high. 
1200 
8.34= weight of water per gallon. 



4800 
3600 
9600 



33,000) 10008.00(.3 
99000 



10800 

Usually 25 per cent, is added for friction, therefore adding 
to 

.3 X 25% = .075 + .3 = .375 H. P. 

+ = plus, or the sign of addition; as, 1605 + 924 = 2529 
— = minus, or the sign of subtraction; as, 1605 — 924 = 681 
X = multiply, or the sign of multiplication; as, — 

' 1605 
924 
6420 
3210 
14445 



1483020 



USEFUL INFORMATION 247 

-T- or - X 2 2 - = divide, or the sign of division; as, — 

1605)1483020(924 
14445 



3852 
3210 

6420 

6420 

. = decimal point, or by its position it indicates the value of 
a number; as,— 

157 = one hundred and fifty-seven. 
15.7 = fifteen and seven-tenths. 
1.57 =one and fifty-seven hundredths. 
.157 = one hundred and fifty-seven thousandths. 

(20) 2 = to be squared, or that the number is to be multi- 
plied by itself; as, — 

(20) 2 = 20 
20 
"400 

(20) 3 = to be cubed, or that the number is to be multiplied 
by itself twice; as, — 

(20) 3 = 20 
20 
~400 

20 
8000 

: :: :.= a proportion, as 4 : 12 :: 8 : 24, and is read, Four is 
to twelve as eight is to twenty-four. 

-\| = a radial sign, and means that a root is to be extracted 
from the number contained beneath it. When no prefix is 
observed, it applies to square root, as ^81 = 9. 



248 PRACTICAL STATIONARY ENGINEERING 



Square Root. 

Rule. — Separate the given number into as many divisions 
or periods as possible of two figures each. Find the greatest 
square in the left-hand period, write the root of it at the right 
of the given number, same as for a quotient, and subtract 
the second power from the left-hand period. Bring down the 
next period to the right of the remainder for a new dividend, 
and double the root already found for a trial divisor. Find 
how many times this divisor is contained in the dividend 
(exclusive of the right-hand figure), and write the quotient as 
the next figure of the root. Annex the last root figure to the 
trial divisor for the true divisor, multiply by the last root 
figure, and subtract the product from the dividend. To the 
remainder bring down the next period for a new dividend. 
Double the root already found for a new trial divisor, and con- 
tinue the operation as before until all the periods' have been 
brought down. 



Exarrvple. — Find the square root of 278784. 

A/278784 (528 
25 



102)287 
204 

1048)8384 
8384 

Proof. 528 X 528 = 278784. 

A power of a number is the result obtained by taking that 
quantity a certain number of times for a factor. The 1st 
power is the root, or the number involved. The 2d power is 
the product multiplied by itself. The 3d power is the root 
used three times. 



USEFUL INFORMATION 249 

Find the 5th power of 4. 

4= 1st power. 
4 

16 = 2d power. 
4 
64 = 3d power. 
4 
256 = 4th power. 

4 
1024 = 5th power. 

Avoirdupois or Commercial Weight. 
27.34375 grains =1 drachm. 
16 drachms =1 ounce = 437.5 grains. 
16 ounces =1 pound = 256 drachms = 7,000 grains. 

28 pounds =1 quarter = 448 ounces. 

4 quarters =1 cwt. = 112 lbs. 
20 cwts. = 1 ton = 80 quarters = 2,240 lbs. 

Long Measure. 
By law the United States standards of length and weight 
are made equal to the British. 

12 inches =1 foot. 

3 feet = 1 yard = 36 inches = .9143919 metre. 

5J yards =1 rod, pole, or perch = 16J feet. 
40 rods = 1 furlong. 

8 furlongs = 1 mile = 5,280 feet = 63,360 inches. 

3 miles = 1 league. 



250 



PRACTICAL STATIONARY ENGINEERING 



Inches and their Equivalent Decimal Values in Parts 
of a Foot. 



Inches. 


Fraction of Foot. 


Decimal Part of Foot. 


1 


tV 


.0833 


2 


i 


.1667 


3 


1 
4 


.25 


4 


i 


.3333 


5 


A 


.4167 


6 


1 


.5 


7 


r\ 


.5833 


8 


2 
3 


.6667 


9 


1 


.75 


10 


# 


.8333 


11 


1 1 

T5 


.9167 


12 


1 


1.0 



Fractional Parts of an Inch and their Equivalent 
Decimal Values in Parts of a Foot. 



Fractions of an 
Inch. 


Decimals of Foot. 


Fractions of an 
Inch. 


Decimals of Foot. 


IS 

i 


.0052 
.0104 


9 
T6 

1 


.0469 
.0521 


ft 
1 

4 


.0156 
.0208 


1 1 
T6 
3 
4 


.0573 
.0625 


I 


.0260 
.0313 


11 


.0677 
.0729 


7 
T6" 

1 
2 


.0365 
.0417 


1 5 

T6" 

1 


.0781 
.0833 



Square or Land Measure. 
144 square inches =1 square foot. 
9 square feet = 1 square yard. 
30^ square yards = 1 square rod. 
40 square rods = 1 rood. 
4 roods =1 acre = 43,560 square feet* 



USEFUL INFORMATION 251 

In the United States surveys a section of land is 1 mile 
square, or 640 acres. 

A square acre is 208.71 feet on each side. 
A circular acre is 235.504 feet in diameter. 

Cubic or Solid Measure. 

1,728 cubic inches = l cubic foot. 
27 cubic feet =1 cubic yard. 

A cord of wood, being 4X4X8 feet, contains 128 cubic 
feet. A ton, 2,240 pounds of Pennsylvania anthracite coal in 
size for domestic use, occupies from 41 to 43 cubic feet; bitu- 
minous coal, 44 to 48 cubic feet; coke, 80 cubic feet. 

Liquid Measure. 

4 gills =1 pint. 

2 pints =1 quart. 

4 quarts=l galIon = 231 cubic inches. 

A cylinder 3^ inches in diameter and 6 inches high will 
hold almost exactly one quart, and one 7 inches in diameter 
and 6 inches high will hold very nearly one gallon. 

This United States gallon is only .8333 of the British imperial 
gallon. A cubic foot contains about 7^ United States gal- 
lons. 

Dry Measure. 

2 pints =1 quart. 
8 quarts =1 peck. 
4 pecks = 1 bushel. 

Four quarts in dry measure contain 268.8 cubic inches, or 
.96945 of the British imperial gallon. The flour barrel should 
contain 3.75 cubic feet and 196 pounds. 



252 practical stationary engineering 

Mensuration. 

Mensuration of Surfaces. 

Area of any parallelogram = base X perpendicular height. 

Area of any triangle = base X i perpendicular height. 

Area of any circle = diameter 2 X .7854/ 

Area of sector of circle =arc X i radius. 

Area of segment of circle =area of sector of equal radius, 

less area of triangle. 
Surface of cylinder = area of both ends -|- length X 

circumference. 
Surface of cone = area of base -f- circumference 

of base X i slant height. 
Surface of sphere = diameter 2 X 3.1415. 

Surface of frustum = sum of girt at both ends X 

\ slant height + area of 

both ends. 

Properties of the Circle. 

Diameter X 3.14159 = circumference. 
Diameter X .8862 =side of an equal square. 
Diameter X .7071 = side of an inscribed square. 
Diameter 2 X .7854 =area of circle. 
Radius X 6.28318 = circumference. 
Circumference -¥• 3.14159 = diameter. 

The circle contains a greater area than any plane figure, 
bounded by an equal perimeter or outline. 

The areas of circles are to each other as the squares of their 
diameters. 

Any circle whose diameter is double that of another con- 
tains four times the area of the other. 

Area of a circle is equal to the area of a triangle whose base 
equals the circumference and perpendicular equals the radius. 



USEFUL INFORMATION 



253 



Mensuration of Solids. 



Cylinder 

Sphere 

Segment of sphere 



Cone or pyramid 
Frustum of a cone 

Frustum of a pyramid = 

Solidity of wedge 
Frustum of a wedge 
Solidity of a ring 



= area of one end X length. 

= cube of diameter X .5236. 

= square root of the height added 
to three times the square of 
radius of base X by height 
and by .5236. 

= area of base X J perpendicular 
height. 

= product of diameter of both 
ends -\- sum of their squares 
X perpendicular height X 
.2618. 
sum of the areas of the two ends 
+ square root of their prod- 
uct X by J of the perpen- 
dicular height, 
area of base X \ perpendicular 

height. 
\ perpendicular height X sum of 

the areas of the two ends, 
thickness -f- inner diameter X 
square of the thickness X 
2.4674. 



CEMENTS. 

Fine cast-iron borings 98 parts 

Flour of sulphur , 1 part 

Sal-ammoniac 1 " 

Mix dry, and, when required for use, dissolve in boiling 
water. This cement sets quickly. 



254 PRACTICAL STATIONARY ENGINEERING 

A Slow-setting Cement. 

Fine cast-iron borings 197 parts 

Flour of sulphur 1 part 

Sal-ammoniac 2 parts 

Mix dry, and, when required for use, mix with boiling water. 
For any cement the iron borings should be perfectly free 
from grease, and, if nothing but greasy material is available, 
boil it in a strong solution of common washing soda. 

For Mouth-pieces of Clay Retorts. 

Three-fourths fire clay, one-fourth iron borings. When 
wanted for use, mix with ammoniacal water. Use no sul- 
phur. 

For Steam and Gas Pipes. 

The following mixture is said to make a cement for steam 
and gas pipes impermeable by air or water, hot or cold: — 

Finely powdered graphite 6 parts 

Slacked lime 3 " 

Sulphur 8 " 

Boiled oil - 7 " 

The mass must be well kneaded until the mixture is perfect. 

A gallon of water (United States standard) weighs 8J pounds, 
and contains 231 cubic inches. 

A cubic foot of water weighs 62^ pounds, and contains 
1,728 cubic inches, or 1\ gallons. 

Each nominal horse power of boilers requires 1 cubic foot 
of water per hour. 

In calculating horse power of steam boilers, consider for: — 

Tubular boilers 15 square feet of heating surface equivalent 
to 1 horse power. 



USEFUL INFORMATION 255 

Flue boilers 12 square feet of heating surface equivalent to 

1 horse power. 
Cylinder boilers 10 square feet of heating surface equivalent to 

1 horse power. 

To find the area of a piston, square the diameter and mul- 
tiply by .7854. 

To find the pressure in pounds per square inch of a column 
of water, multiply the height of the' column in feet by .434. 

Every stroke an engine makes above its regular speed 
is a waste of steam. An engine, when load is thrown off, 
increases its speed, and decreases it when additional load 
is put on. 

Steam is calculated in pounds per square inch above the 
atmospheric pressure of 14.7. The nearer the line of ex- 
pansion approaches that of the atmosphere, the greater the 
power derived from the volume of steam. 



256 



PRACTICAL STATIONARY ENGINEERING 



Table for the Conversion of Degrees of the Centigrade 
Thermometer into Degrees of Fahrenheit's Scale. 



Cent. 


Fahr. 


Cent. 


Fahr. 


Cent. 


Fahr. 


Cent. 


Fahr. 





32. 


26 


78.8 


51 


123.8 


76 


168.8 


1 


33.8 


27 


80.6 


52 


125.6 


77 


170.6 


2 


35.6 


28 


82.4 


53 


127.4 


78 


172.4 


3 


37.4 


29 


84.2 


54 


129.2 


79 


174.2 


4 


39.2 


30 


86.0 


55 


131.0 


80 


176.0 


5 


41.0 


31 


87.8 


56 


132.8 


81 


177.8 


6 


42.8 


32 


89.6 


57 


134.6 


82 


179.6 


7 


44.6 


33 


91.4 


58 


136.4 


83 


181.4 


8 


46.4 


34 


93.2 


59 


138.2 


84 


183.2 


9 


48.2 


35 


95.0 


60 


140.0 


85 


185.0 


10 


50.0 


36 


96.8 


61 


141.8 


86 


186.8 


11 


51.8 


37 


98.6 


62 


143.6 


87 


188.6 


12 


53.6 


38 


100.4 


63 


145.4 


88 


190.4 


13 


55.4 


39 


102.2 


64 


147.2 


89 


192.2 


14 


57.2 


40 


104.0 


65 


149.0 


90 


194.0 


15 


59.0 


• 41 


105.8 


66 


150.8 


91 


195.8 


16 


60.8 


42 


107.6 


67 


152.6 


92 


197.6 


17 


62.6 


43 


109.4 


68 


154.4 


93 


199.4 


18 


64.4 


44 


111.2 


69 


156.2 


94 


201.2 


19 


66.2 


45 


113.0 


70 


158.0 


95 


203.0 


20 


68.0 


46 


114.8 


71 


159.8 


96 


204.8 


21 


69.8 


47 


116.6 


72 


161.6 


97 


206.6 


22 


71.6 


48 


118.4 


73 


163.4 


98 


208.4 


23 


73.4 


49 


120.2 


74 


165.2 


99 


210.2 


24 


75.2 


50 


122.0 


75 


167.0 


100 


212.0 


25 


77.0 















USEFUL INFORMATION 

Properties of Saturated Steam. 



257 









Total Heat 










Gauge 
Press- 


Abso- 
lute 
Press- 


Temper- 


above 


32 J F. 


Latent 
Heat L 


Relative 
Volume 


Volume 
Cubic 


Weight 
of 1 


ure, 






Pounds 
per 


Pounds 


Fahren- 


In the 
Water 


In the 
Steam 


=H—h 
Heat- 


of Water 
at39°F. 


Feet in 
1 Pound 


Cubic 

Foot 

Steam, 

Pound. 


Square 
Inch. 


per 
Square 




h 
Heat- 


H 
Heat- 


units. 


= 1. 


of Steam. 








units. 


units. 










5.3 


20 


227.9 


197.0 


1151.5 


954.4 


1231. 


19.72 


.05070 


10.3 


25 


240.0 


209.3 


1155.1 


945.8 


998.4 


15.99 


.06253 


15.3 


30 


250.2 


219.7 


1158.3 


938.9 


841.3 


13.48 


.07420 


20.3 


35 


259.2 


228.8 


1161.0 


932.2 


727.9 


11.66 


.08576 


25.3 


40 


267.1 


236.9 


1163.4 


926.5 


642.0 


10.28 


.09721 


30.3 


45 


274.3 


244.3 


1165.6 


921.3 


574.7 


9.21 


.1086 


35.3 


50 


280.9 


251.0 


1167.6 


916.6 


520.5 


8.34 


.1198 


40.3 


55 


286.9 


257.2 


1169.4 


912.3 


475.9 


7.63 


.1311 


45.3 


60 


292.5 


262.9 


1171.2 


908.2 


438.5 


7.03 


.1422 


50.3 


65 


297.8 


268.3 


1172.8 


904.5 


406.6 


6.53 


.1533 


55.3 


70 


302.7 


273.4 


1174.3 


900.9 


379.3 


6.09 


.1643 


60.3 


75 


307.4 


278.2 


1175.7 


897.5 


355.5 


5.71 


.1753 


65.3 


80 


311.8 


282.7 


1177.0 


894.3 


334.5 


5.37 


.1862 


70.3 


85 


316.0 


287.0 


1178.3 


891.3 


315.9 


5.07 


.1971 


75.3 


90 


320.0 


291.2 


1179.6 


888.4 


299.4 


4.81 


.2080 


80.3 


95 


323.9 


295.1 


1180.7 


885.6 


284.5 


4.57 


• .2188 


85.3 


100 


327.6 


298.9 


1181.8 


882.9 


271.1 


4.36 


.2296 


90.3 


105 


331.1 


302.6 


1182.9 


880.3 


258.9 


4.16 


.2403 


95.3 


110 


334.5 


306.1 


1184.0 


877.9 


247.8 


3.98 


.2510 


100.3 


115 


337.8 


309.5 


1185.0 


875.5 


237.6 


3.82 


.2617 


105.3 


120 


341.0 


312.8 


.9 


873.2 


228.3 


3.67 


.2724 


110.3 


125 


344.1 


316.0 


1186.9 


870.9 


219.6 


3.53 


.2830 


115.3 


130 


347.1 


319.1 


1187.8 


868.7 


211.6 


3.41 


.2936 


120.3 


135 


350.0 


322.1 


1188.7 


866.6 


204.2 


3.29 


.3042 


125.3 


140 


352.8 


325.0 


1189.5 


864.6 


197.3 


3.18 


.3147 


130.3 


145 


355.5 


327.8 


1190.4 


862.6 


190.9 


3.07 


.3253 


135.3 


150 


358.2 


330.6 


1191.2 


860.6 


184.9 


2.98 


.3358 


140.3 


155 


360.7 


333.2 


1192.0 


858.7 


179.2 


2.89 


.3463 


145.3 


160 


363.3 


335.9 


.7 


856.9 


173.9 


2.80 


.3567 


150.3 


165 


365.7 


338.4 


1193.5 


855.1 


169.0 


2.72 


.3671 


155.3 


170 


368.2 


340.9 


1194.2 


853.3 


164.3 


2.65 


.3775 


160.3 


175 


370.5 


343.4 


.9 


851.6 


159.8 


2.58 


.3879 


165.3 


180 


372.8 


345.8 


1195.7 


849.9 


155.6 


2.51 


.3983 


170.3 


185 


375.1 


348.1 


1196.3 


848.2 


151.6 


2.45 


.4087 


175.3 


190 


377.3 


350.4 


1197.0 


846.6 


147.8 


2.39 


.4191 


180.3 


195 


379.5 


352.7 


.7 


845.0 


^ 144.2 


2.33 


.4296 


185.3 


200 


381.6 


354.9 


1198.3 


843.4 


140.8 


2.27 


.4400 


190.3 


205 


383.7 


357.1 


1199.0 


841.9 


137.5 


2.22 


.4503 


195.3 


210 


385.7 


359.2 


.6 


840.4 


134.5 


2.17 


.4605 


200.3 


215 


387.7 


361.3 


1200.2 


838.9 


131.5 


2.12 


.4707 



258 PRACTICAL STATIONARY ENGINEERING 

Area of Circles. 



Diam. 


Area. 


Diam. 


Area. 


Diam. 


Area. 


Diam. 


Area. 


1-64 


.000192 


5. 


19.635 


12. 


113.098 


19. 


283.529 


1-32 


.000767 


•* 


20.629 


.* 


115.466 


.* 


287.272 


1-16 


.003068 


•i 


21.6476 


■\ 


117.859 


-i 


291.04 


1-8 


.012272 


•1 


22.6907 


•1 


120.277 


•1 


294.832 


3-16 


.027612 


•4 


23.7583 


•1 


122.719 


•h 


298.648 


1-4 


.049087 


•1 


24.8505 


4 


125.185 


•f 


302.489 


5-16 


.076699 


•1 


25.9673 


3 


127.677 


•1 


306.355 


3-8 


.110447 


•1 


27.1086 


'* 


130.192 


•1 


310.245 


7-16 


.15033 


6. 


28.2744 


13. 


132.733 


20. 


314.16 


1-2 


.19635 


■i 


29.4648 


.£ 


135.297 


.* 


318.099 


9-16 


.248505 


■i 


30.6797 


i 


137.887 


•\ 


322.063 


5-8 


.306796 


•1 


31.9191 


"f 


140.501 


•1 


326.051 


11-16 


.371224 


•4 


33.1831 


•2 


143.139 


• 1 


330.064 


3-4 


.441787 


5 

•8 


34.4717 


•f 


145.802 


■1 


334.102 


13-16 


.518487 


■1 


35.7848 


•1 


148.49 


•I 


338.164 


7-8 


.661322 


•i 


37.1224 


■I" 


151.202 


■l 


342.25 


15-16 


.690292 


• 7. 


38.4846 


14. 


153.938 


21. 


346.361 


1. 


.7854 


■i 


39.8713 


•i 


156.7 


.* 


350.497 


.* 


.99402 


•l 


41.2826 


•i 


159.485 


•1 


354.657 


•i 


1.2272 


| 


42.7184 


3 

•8 


162.296 


•1 


358.842 


•1 


1.4849 


•4 


44.1787 


■h 


165.13 


.4 


363.051 


•4 


1.7671 


•f 


45.6636 


■1 


167.99 


•f 


367.285 


•1 


2.0739 


3 


47.1731 


2. 


170.874 


•1 


371.543 


3 
•4 


2.4053 


.'! 


48.7071 


•'I 


173.782 


•1 


375.826 


•1 


2.7612 


8. 


50.2656 


15. 


176.715 


22. 


380.134 


2. 


3.1416 


| 


51.8487 


.£ 


179.673 


.* 


384.466 


■* 


3.5466 




53.4563 


•4 


182.655 


•\ 


388.822 


•i 


3.9761 


3 

•8 


55.0884 


•1 


185.661 


•f 


393.203 


•1 


4.4301 


•\ 


56.7451 


•4 


188.692 


•4 


397.609 


■4 


4.9087 


•f 


58.4264 


•f 


191.748 


•f 


402.038 


•f 


5.4119 


•1 


60.1322 


3. 


194.828 


•! 


406.494 


•1 


5.9396 


•1 


61.8625 


•l 


197.933 


■1 


410.973 


•J 


6.4918 


9. 


63.6174 


16. 


201.062 


23. 


415.477 


3. 


7.0686 


4 


65.3968 


•i 


204.216 


.* 


420.004 


•* 


7.6699 


•i 


67.2008 


•i 


207.395 


•i 


424.558 


•i 


8.2958 


•1 


69.0293 


i 


210.598 


•1 


429.135 


3 

•8 


8.9462 


•4 


70.8823 


i 

•2 


213.825 


.4 


433.737 


•4 


9.6211 


•1 


72.7599 


•1 


217.077 


•f 


439.364 


•f 


10.3206 


•1 


74.6621 


^ 


220.354 


•1 


443.015 


i 


11.0447 


•1 


76.5888 


i 


223.655 


■i 


447.69 


•'! 


11.7933 


10. 


78.54 


17. 


226.981 


24. 


452.39 


4. 


12.5664 


.£ 


80.5158 


.£ 


230.331 


.* 


457.115 


.* 


13.3641 


•i 


82.5161 


i 


233.706 


■\ 


461.864 


■i 


14.1863 


•1 


84.5409 


i 


237.105 


•1 


466.638 


•f 


15.033 


•1 


86.5903 


■4 


240.529 


•4 


471.436 


•4 


15.9043 


•f 


88.6643 


•f 


243.977 


•1 


476.259 


•1 


16.8002 


3 
•4 


90.7628 


3 
•4 


247.45 


3 


481.107 


•1 


17.7206 


•1 


92.8858 


•1 


250.948 


i 


485.479 


•1 


18.6655 


11. 


95.0334 


18. 


254.47 


25. 


490.875 


— 


— 


•1 


97.2055 


• 1 


258.016 


.* 


495.796 


— 


— 


.i 


99.4022 


i 


261.587 


•i 


500.742 


— 


— 


•I 


101.6234 


•1 


265.183 


•f 


505.712 


— " 


— 


•1 


103.8691 


■4 


268.803 


.4 


510.706 


— 


— 


•f 


106.1394 


•t 


272.448 


•1 


515.726 


— 


— 


3 
•4 


108.4343 


3 


276.117 


3 


520.769 






•1 


110.7537 


.'! 


279.811 


•1 

26. 


525.838 
530.93 



USEFUL INFORMATION 



259 



Number of 
Threads 
per Inch 
of Screw. 


H|N lH|(N rH|lN tH|M 

NO)00^^rHiHrHrH0000C00000 000000G00000 

(Mr-Hl-lT-lT-li-lrHl-lrH 


o 

0>fci c 

a 


kCONhiOOOOO^NWMOOON^NOOONh 

n °6666HHddcoicNoi6(N^o6(ro(X)'*6 


Length of 

Pipe 
containing 
One Cubic 

Foot. 


w . OOiOi|0®^OCOH^iCCOO(NC5l>00(MOO 

gdiOHNootodddoi^HCJN^mNNH 

feOMiONNOOiN^COHHH 
iO CO 1>- tJh cq i— i 


3 


cS(MOJiOiOCD»OOCOCOai(MOCCOONO(NHCO 

^dddddHiNd^dddiodTtiTjiiooocod 




, MHCDOOCON 

»N^-H^^(^coOO»OCOCON0030©N01COa) 
jiOOOOCOCDOiCCiOOOCOOOCOCOOOOCOCOCOCO 

go^^co^oq^pcoi>"Cooqi>-OiOiGOt^ocooo 
•- 1 o o o o o-o T^c^'cd^t^cic^LoaicxJoocDcdoo 


Length of 
Pipe per 

Sq. Ft. Of 
Outside 
Surface. 


■£ ^MOOCOOOHHiMOiO^OMNO^OiiO 

«^qcqiocoqcoqcqcoqoiGONcDioio^coco 


Length of 
Pipe per 

Sq. Ft. of 
Inside 
Surface. 


iCOi00HQ0NiONO5 00N ^ 00 IO r- 1 
*>lOONCOCONON^^^N^^iOCO^N(MOO 


lag 

CD § ° 


»)• (M CD HM OJ^iOOiHiMiriONOOiOrO^COCOW 
«NO3(Mi0CXC0HCDCOC00iCDC0ONHiO03C0N 

^woHcotNHoqoj^qoiiOrHN^oqcjio^N 

H^rnddcO^iOiONciod^kONOCONOCO 


£ 3 c 

<U V 0> 

!'6& 


•00^(MNOiWiOrH^TriOCDOOCOOi^rOCDNiO 
o^^iOiOOOOiCOOOiOCO^^iC^iCCDNNN 
^OOHiqOiONCOq^NCDHOHOCqOON^ 


Actual 

Inside 

Diameter. 


„ O^'^fC^00OHN00t>a)CD(X)i0>OC0(MH0i 
«JNOOiMW^OOHCOOCD^(NO^ONOOOH 

■^(>iw^cDooqcocoq^qioq»oqqqoioo 
HodddoHHHdNcoco^^iodNNdd 

1 — 1 


*_2 a> 


aiOOGOr-iOCO^OiO^^ H NONNaiO'H(M^CD 
^OOOOOOOOOOOOOOOOOOOO 


I'll 


K -io>o iO tOLO CO iCiOiCOO 
SO^N^iOrHCO 1>-1>- CD(N(M (NGOiC 

^lOOOOOCOCDOJCqOOiOqiOO'OOCOCO'CDN 

SdddoHHHHNiNco^^ioiodNoodd 


Inside 
Diameter 
(Nominal). 


lH|00 H"* wl<» Hc^ "I"* H^M<N H|N H|N ih|N 

HHHC^C^COCO^^iOCONOOffiO 

1— 1 



260 



PRACTICAL STATIONARY ENGINEERING 



IS* 

Ota. u 

£^ S 


Pounds. 
.70 
.90 

1.24 

1.66 

1.91 

2.16 

2.75 

3.04 

3.33 

3.96 

4.28 

4.60 

5.47 

6.17 

7.58 
10.16 
11.90 
13.65 
16.76 
21.00 
25.00 
28.50 
32.06 
36.00 
40.60 
45.20 
49.90 
54.81 
59.47 
66.76 
73.40 


03 

_cc co 


CO 

JS 00C^C0O^r^O^COC5C^Tt<COOC01>00COi-i-*C0a>C0C0i--iC000CO<Ni0C0 

oNNN^rtfficoffiqwcqq^ojcDM^NcpioqoNOiNqa^iOrHM 
.2 cj^^^coco^'io^QOoii^c^^cnoooocJ^oo^coc^cdcdr^'ccThco^'cd 

i-lrHHiHNCOiOCONffliHMiONOWOOCHTli 
• HnHrtNNNNMCC 


co . 

•- CO 


CO 

^3 1>C003T-H>0'-iaiCOOO<MiOC003(MC3300C3i05l^r^rtHOOOOi-<CO<N(MOt^'-i 
O lO OS CO C3 IC CO O O CO —I TO CO C3 rn T}i iq 00 I> Ol OS Tt t^. ,-h h t>- CO <N_ <M OS CO CO 

i-i tHr-li-HCqeO' , *lOI>000(N'*CCOOi-(COC005CN 

d- -^^^c^cnco 
a; 


Length 
of Tube 
per Sq. 
Foot, 
Outside 
Surface. 


^^iOrt < Q0005C<10^^t^O^'^lO^COCO , *t^CNOO-<*r-iOit^«OCOCNI'-i00500 

>J oo o »o i-h as co iq co <m r-n cq cq cq oq i> cq iq ■* ■* co co co <m cni nnnnnhh 


Length 
of Tube 
per Sq. 
Foot, 
Inside 
Surface. 


-*e'cO>OCO^-HiOI^Ot^COt^000500!^(^0^05COCOOOOCO'*COr-iOOJOO 

g rh ■* oq ■* r-; oq cq »q eo cn t-j cq © oi oq cq »q iq Tt; co oo co co n«s««nhh 

^^'COC<ic<icNr-5i-3rHT-5rH^T-Hi-H 


05,2 

:HS CO- 
CO g O 


S^C<lrHCSC>OCOiCCOMrHO^OOCOCOO^CXCO^^iCC35-*OOC<lCOO'*C33COI> 

x: rnc»i>^wooo«q^No;^WTHi>oqojrHeflTjjiq«0(»asrHN^»qoQOOJ 
2eo^^'ioco^t^o6oJdd^c4^'^o6r^wo6r^^'^drot^dcocD^(Nio' 

^G ^H ^H i-H rH t-i ^H r-i C^ CM (M CO CO CO ■* "* ■* lO »0 »0 lO CO CO 


lis 

Cog 

O 


SoOt^C»OCOOOt^iO^COTt<COiCC<l'--iO'--iOOiCt^t^-CO'*^Hi3iCDCOi-HO(NCO 

j3 cq^--;0^cq^rHi35t>.^c^oi>cqoqcqo^cqop^^ico^^^cq^ 
Hc^'cc^^'»ddt^t^o6ddi-HrHco^'^dro^dMdo5<NooOrHTi ; t>deo 

^ _ ^H^H^H^H^H^H(N<N<MCOCOCOCO^T}HTiHlOlO»OCOCO 


C0.JJ 


(BlOOeOCOO'COOCOOOi-KO»-i'^ |, *iMC35iOCOi-it^CO'*CMOOOiCCOT-iOCOCM 

_a Wi-icoioooocNiot^o<Nmr^cN^cocococoiqio>oiq'C , ^Th , *Tfi^coco 
2 drHrHrHiHiNWNc^roroco^^^^dt^ooddrHNco^^dt^oocJd 

£ rHHHHHrtHMHHlN 


Nearest 
Birmingham 
Wire Gauge 
Thickness. 


CO 

M 

§ + * Md H|N HIN 

Q iO^^COCOCOC<)C^C<Ii-4i--4i-i0003000000l>COlC' , cH , *COCO(NCNlr-(rHOO 


If 

C8.2 


<B OKNCOiOiOiOaOOlOOO^^QOiOlfliOOCOOOOOOOaO^NOOO 
rj l^^OOC^C^OiOOOCMCNlC5COCO , *COCOCOOOOC>lC-)CO^t'iOt^00050<N-* 

OOOOOOOrt-HHrtHWrtHHHrHT-(rt(MMNCqNCKNWNmP3W 

a 


.a co 
°5 


fll r+Jr-tNMW ^+*H|NMM i4*HlNP!H i-(N 

^rHrHrH^C<lCNC^CNCOCOCOCO^TjH^COt>.00050THCNMT^lOCOt^OOC330'-i 

c 



OCT 23 1909 



